There are tears in the audience as Patrick Darling’s song begins to play. It’s a heartfelt song written for his great-grandfather, whom he never got the chance to meet. But this performance is emotional for another reason: It’s Darling’s first time on stage with his bandmates since he lost the ability to sing two years ago.

The 32-year-old musician was diagnosed with amyotrophic lateral sclerosis (ALS) when he was 29 years old. Like other types of motor neuron disease (MND), it affects nerves that supply the body’s muscles. People with ALS eventually lose the ability to control their muscles, including those that allow them to move, speak, and breathe.

Darling’s last stage performance was over two years ago. By that point, he had already lost the ability to stand and play his instruments and was struggling to sing or speak. But recently, he was able to re-create his lost voice using an AI tool trained on snippets of old audio recordings. Another AI tool has enabled him to use this “voice clone” to compose new songs. Darling is able to make music again.

“Sadly, I have lost the ability to sing and play my instruments,” Darling said on stage at the event, which took place in London on Wednesday, using his voice clone. “Despite this, most of my time these days is spent still continuing to compose and produce my music. Doing so feels more important than ever to me now.”

Losing a voice

Darling says he’s been a musician and a composer since he was around 14 years old. “I learned to play bass guitar, acoustic guitar, piano, melodica, mandolin, and tenor banjo,” he said at the event. “My biggest love, though, was singing.”

He met bandmate Nick Cocking over 10 years ago, while he was still a university student, says Cocking. Darling joined Cocking’s Irish folk outfit, the Ceili House Band, shortly afterwards, and their first gig together was in April 2014. Darling, who joined the band as a singer and guitarist, “elevated the musicianship of the band,” says Cocking.

But a few years ago, Cocking and his other bandmates started noticing changes in Darling. He became clumsy, says Cocking. He recalls one night when the band had to walk across the city of Cardiff in the rain: “He just kept slipping and falling, tripping on paving slabs and things like that.” 

He didn’t think too much of it at the time, but Darling’s symptoms continued to worsen. The disease affected his legs first, and in August 2023, he started needing to sit during performances. Then he started to lose the use of his hands. “Eventually he couldn’t play the guitar or the banjo anymore,” says Cocking.

By April 2024, Darling was struggling to talk and breathe at the same time, says Cocking. For that performance, the band carried Darling on stage. “He called me the day after and said he couldn’t do it anymore,” Cocking says, his voice breaking. “By June 2024, it was done.” It was the last time the band played together.

Re-creating a voice

Darling was put in touch with a speech therapist, who raised the possibility of “banking” his voice. People who are losing the ability to speak can opt to record themselves speaking and use those recordings to create speech sounds that can then be activated with typed text, whether by hand or perhaps using a device controlled by eye movements.

Some users have found these tools to be robotic sounding. But Darling had another issue. “By that stage, my voice had already changed,” he said at the event. “It felt like we were saving the wrong voice.”

Then another speech therapist introduced him to a different technology. Richard Cave is a speech and language therapist and a researcher at University College London. He is also a consultant for ElevenLabs, an AI company that develops agents and audio, speech, video, and music tools. One of these tools can create “voice clones”—realistic mimics of real voices that can be generated from minutes, or even seconds, of a person’s recorded voice.

Last year, ElevenLabs launched an impact program with a promise to provide free licenses to these tools for people who have lost their voices to ALS or other diseases, like head and neck cancer or stroke. 

The tool is already helping some of those users. “We’re not really improving how quickly they’re able to communicate, or all of the difficulties that individuals with MND are going through physically, with eating and breathing,” says Gabi Leibowitz, a speech therapist who leads the program. “But what we are doing is giving them a way … to create again, to thrive.” Users are able to stay in their jobs longer and “continue to do the things that make them feel like human beings,” she says.

Cave worked with Darling to use the tool to re-create his lost speaking voice from older recordings.

“The first time I heard the voice, I thought it was amazing,” Darling said at the event, using the voice clone. “It sounded exactly like I had before, and you literally wouldn’t be able to tell the difference,” he said. “I will not say what the first word I made my new voice say, but I can tell you that it began with ‘f’ and ended in ‘k.’”

Re-creating his singing voice wasn’t as easy. The tool typically requires around 10 minutes of clear audio to generate a clone. “I had no high-quality recordings of myself singing,” Darling said. “We had to use audio from videos on people’s phones, shot in noisy pubs, and a couple of recordings of me singing in my kitchen.” Still, those snippets were enough to create a “synthetic version of [Darling’s] singing voice,” says Cave.

In the recordings, Darling sounded a little raspy and “was a bit off” on some of the notes, says Cave. The voice clone has the same qualities. It doesn’t sound perfect, Cave says—it sounds human.

“The ElevenLabs voice that we’ve created is wonderful,” Darling said at the event. “It definitely sounds like me—[it] just kind of feels like a different version of me.”

ElevenLabs has also developed an AI music generator called Eleven Music. The tool allows users to compose tracks, using text prompts to choose the musical style. Several well-known artists have also partnered with the company to license AI clones of their voices, including the actor Michael Caine, whose voice clone is being used to narrate an upcoming ElevenLabs documentary. Last month, the company released an album of 11 tracks created using the tool. “The Liza Minnelli track is really a banger,” says Cave.

Eleven Music can generate a song in a minute, but Darling and Cave spent around six weeks fine-tuning Darling’s song. Using text prompts, any user can “create music and add lyrics in any style [they like],” says Cave. Darling likes Irish folk, but Cave has also worked with a man in Colombia who is creating Colombian folk music. (The ElevenLabs tool is currently available in 74 languages.)

Back on stage

Last month, Cocking got a call from Cave, who sent him Darling’s completed track. “I heard the first two or three words he sang, and I had to turn it off,” he says. “I was just in bits, in tears. It took me a good half a dozen times to make it to the end of the track.”

Darling and Cave were making plans to perform the track live at the ElevenLabs summit in London on Wednesday, February 11. So Cocking and bandmate Hari Ma each arranged accompanying parts to play on the mandolin and fiddle. They had a couple of weeks to rehearse before they joined Darling on stage, two years after their last performance together.

“I wheeled him out on stage, and neither of us could believe it was happening,” says Cave. “He was thrilled.” The song was played as Darling remained on stage, and Cocking and Ma played their instruments live.

Cocking and Cave say Darling plans to continue to use the tools to make music. Cocking says he hopes to perform with Darling again but acknowledges that, given the nature of ALS, it is difficult to make long-term plans.

“It’s so bittersweet,” says Cocking. “But getting up on stage and seeing Patrick there filled me with absolute joy. I know Patrick really enjoyed it as well. We’ve been talking about it … He was really, really proud.”

ELEVENLABS/AMPLIFY

Following publication of this story, Politico reported Jim O’Neill would be leaving his current roles within the Department of Health and Human Services.

Over the past year, Jim O’Neill has become one of the most powerful people in public health. As the US deputy health secretary, he holds two roles at the top of the country’s federal health and science agencies. He oversees a department with a budget of over a trillion dollars. And he signed the decision memorandum on the US’s deeply controversial new vaccine schedule.

He’s also a longevity enthusiast. In an exclusive interview with MIT Technology Review earlier this month, O’Neill described his plans to increase human healthspan through longevity-focused research supported by ARPA-H, a federal agency dedicated to biomedical breakthroughs. At the same time, he defended reducing the number of broadly recommended childhood vaccines, a move that has been widely criticized by experts in medicine and public health. 

In MIT Technology Review’s profile of O’Neill last year, people working in health policy and consumer advocacy said they found his libertarian views on drug regulation “worrisome” and “antithetical to basic public health.” 

He was later named acting director of the Centers for Disease Control and Prevention, putting him in charge of the nation’s public health agency.

But fellow longevity enthusiasts said they hope O’Neill will bring attention and funding to their cause: the search for treatments that might slow, prevent, or even reverse human aging. Here are some takeaways from the interview. 

Vaccine recommendations could change further

Last month, the US cut the number of vaccines recommended for children. The CDC no longer recommends vaccinations against flu, rotavirus, hepatitis A, or meningococcal disease for all children. The move was widely panned by medical groups and public health experts. Many worry it will become more difficult for children to access those vaccines. The majority of states have rejected the recommendations. 

In the confirmation hearing for his role as deputy secretary of health and human services, which took place in May last year, O’Neill said he supported the CDC’s vaccine schedule. MIT Technology Review asked him if that was the case and, if so, what made him change his mind. “Researching and examining and reviewing safety data and efficacy data about vaccines is one of CDC’s obligations,” he said. “CDC gives important advice about vaccines and should always be open to new data and new ways of looking at data.”

At the beginning of December, O’Neill said, President Donald Trump “asked me to look at what other countries were doing in terms of their vaccine schedules.” He said he spoke to health ministries of other countries and consulted with scientists at the CDC and FDA. “It was suggested to me by lots of the operating divisions that the US focus its recommendations on consensus vaccines of other developed nations—in other words, the most important vaccines that are most often part of the core recommendations of other countries,” he said.

“As a result of that, we did an update to the vaccine schedule to focus on a set of vaccines that are most important for all children.” 

But some experts in public health have said that countries like Denmark and Japan, whose vaccine schedules the new US one was supposedly modeled on, are not really comparable to the US. When asked about these criticisms, O’Neill replied, “A lot of parents feel that … more than 70 vaccine doses given to young children sounds like a really high number, and some of them ask which ones are the most important. I think we helped answer that question in a way that didn’t remove anyone’s access.”

A few weeks after the vaccine recommendations were changed, Kirk Milhoan, who leads the CDC’s Advisory Committee on Immunization Practices, said that vaccinations for measles and polio—which are currently required for entry to public schools—should be optional. (Mehmet Oz, the Center for Medicare and Medicaid Services director, has more recently urged people to “take the [measles] vaccine.”)

“CDC still recommends that all children are vaccinated against diphtheria, tetanus, whooping cough, Haemophilus influenzae type b (Hib), Pneumococcal conjugate, polio, measles, mumps, rubella, and human papillomavirus (HPV), for which there is international consensus, as well as varicella (chickenpox),” he said when asked for his thoughts on this comment.

He also said that current vaccine guidelines are “still subject to new data coming in, new ways of thinking about things.” “CDC, FDA, and NIH are initiating new studies of the safety of immunizations,” he added. “We will continue to ask the Advisory Committee on Immunization Practices to review evidence and make updated recommendations with rigorous science and transparency.”

More support for longevity—but not all science

O’Neill said he wants longevity to become a priority for US health agencies. His ultimate goal, he said, is to “make the damage of aging something that’s under medical control.” It’s “the same way of thinking” as the broader Make America Healthy Again approach, he said: “‘Again’ implies restoration of health, which is what longevity research and therapy is all about.” 

O’Neill said his interest in longevity was ignited by his friend Peter Thiel, the billionaire tech entrepreneur, around 2008 to 2009. It was right around the time O’Neill was finishing up a previous role in HHS, under the Bush administration. O’Neill said Thiel told him he “should really start looking into longevity and the idea that aging damage could be reversible.” “I just got more and more excited about that idea,” he said.

When asked if he’s heard of Vitalism, a philosophical movement for “hardcore” longevity enthusiasts who, broadly, believe that death is wrong, O’Neill replied: “Yes.” 

The Vitalist declaration lists five core statements, including “Death is humanity’s core problem,” “Obviating aging is scientifically plausible,” and “I will carry the message against aging and death.” O’Neill said he agrees with all of them. “I suppose I am [a Vitalist],” he said with a smile, although he’s not a paying member of the foundation behind it.

As deputy secretary of the Department of Health and Human Services, O’Neill assumes a level of responsibility for huge and influential science and health agencies, including the National Institutes of Health (the world’s largest public funder of biomedical research) and the Food and Drug Administration (which oversees drug regulation and is globally influential) as well as the CDC.

Today, he said, he sees support for longevity science from his colleagues within HHS. “If I could describe one common theme to the senior leadership at HHS, obviously it’s to make America healthy again, and reversing aging damage is all about making people healthy again,” he said. “We are refocusing HHS on addressing and reversing chronic disease, and chronic diseases are what drive aging, broadly.”

Over the last year, thousands of NIH grants worth over $2 billion were frozen or terminated, including funds for research on cancer biology, health disparities, neuroscience, and much more. When asked whether any of that funding will be restored, he did not directly address the question, instead noting: “You’ll see a lot of funding more focused on important priorities that actually improve people’s health.”

Watch ARPA-H for news on organ replacements and more

He promised we’ll hear more from ARPA-H, the three-year-old federal agency dedicated to achieving breakthroughs in medical science and biotechnology. It was established with the official goal of promoting “high-risk, high-reward innovation for the development and translation of transformative health technologies.”

O’Neill said that “ARPA-H exists to make the impossible possible in health and medicine.” The agency has a new director—Alicia Jackson, who formerly founded and led a company focused on women’s health and longevity, took on the role in October last year.

O’Neill said he helped recruit Jackson, and that she was hired in part because of her interest in longevity, which will now become a major focus of the agency. He said he meets with her regularly, as well as with Andrew Brack and Jean Hébert, two other longevity supporters who lead departments at ARPA-H. Brack’s program focuses on finding biological markers of aging. Hebert’s aim is to find a way to replace aging brain tissue, bit by bit.  

O’Neill is especially excited by that one, he said. “I would try it … Not today, but … if progress goes in a broadly good direction, I would be open to it. We’re hoping to see significant results in the next few years.”

He’s also enthused by the idea of creating all-new organs for transplantation. “Someday we want to be able to grow new organs, ideally from the patients’ own cells,” O’Neill said. An ARPA-H program will receive $170 million over five years to that end, he adds. “I’m very excited about the potential of ARPA-H and Alicia and Jean and Andrew to really push things forward.”

Longevity lobbyists have a friendly ear

O’Neill said he also regularly talks to the team at the lobbying group Alliance for Longevity Initiatives. The organization, led by Dylan Livingston, played an instrumental role in changing state law in Montana to make experimental therapies more accessible. O’Neill said he hasn’t formally worked with them but thinks that “they’re doing really good work on raising awareness, including on Capitol Hill.”

Livingston has told me that A4LI’s main goals center around increasing support for aging research (possibly via the creation of a new NIH institute entirely dedicated to the subject) and changing laws to make it easier and cheaper to develop and access potential anti-aging therapies.

O’Neill gave the impression that the first goal might be a little overambitious—the number of institutes is down to Congress, he said. “I would like to get really all of the institutes at NIH to think more carefully about how many chronic diseases are usefully thought of as pathologies of aging damage,” he said. There’ll be more federal funding for that research, he said, although he won’t say more for now.

Some members of the longevity community have more radical ideas when it comes to regulation: they want to create their own jurisdictions designed to fast-track the development of longevity drugs and potentially encourage biohacking and self-experimentation. 

It’s a concept that O’Neill has expressed support for in the past. He has posted on X about his support for limiting the role of government, and in support of building “freedom cities”—a similar concept that involves creating new cities on federal land. 

Another longevity enthusiast who supports the concept is Niklas Anzinger, a German tech entrepreneur who is now based in Próspera, a private city within a Honduran “special economic zone,” where residents can make their own suggestions for medical regulations. Anzinger also helped draft Montana’s state law on accessing experimental therapies. O’Neill knows Anzinger and said he talks to him “once or twice a year.”

O’Neill has also supported the idea of seasteading—building new “startup countries” at sea. He served on the board of directors of the Seasteading Institute until March 2024.

In 2009, O’Neill told an audience at a Seasteading Institute conference that “the healthiest societies in 2030 will most likely be on the sea.” When asked if he still thinks that’s the case, he said: “It’s not quite 2030, so I think it’s too soon to say … What I would say now is: the healthiest societies are likely to be the ones that encourage innovation the most.”

We might expect more nutrition advice

When it comes to his own personal ambitions for longevity, O’Neill said, he takes a simple approach that involves minimizing sugar and ultraprocessed food, exercising and sleeping well, and supplementing with vitamin D. He also said he tries to “eat a diet that has plenty of protein and saturated fat,” echoing the new dietary guidance issued by the US Departments of Health and Human Services and Agriculture. That guidance has been criticized by nutrition scientists, who point out that it ignores decades of research into the harms of a diet high in saturated fat.

We can expect to see more nutrition-related updates from HHS, said O’Neill: “We’re doing more research, more randomized controlled trials on nutrition. Nutrition is still not a scientifically solved problem.” Saturated fats are of particular interest, he said. He and his colleagues want to identify “the healthiest fats,” he said. 

“Stay tuned.”

Americans have a new set of diet guidelines. Robert F. Kennedy Jr. has taken an old-fashioned food pyramid, turned it upside down, and plonked a steak and a stick of butter in prime positions.

Kennedy and his Make America Healthy Again mates have long been extolling the virtues of meat and whole-fat dairy, so it wasn’t too surprising to see those foods recommended alongside vegetables and whole grains (despite the well-established fact that too much saturated fat can be extremely bad for you).

Some influencers have taken the meat trend to extremes, following a “carnivore diet.” “The best thing you could do is eliminate out everything except fatty meat and lard,” Anthony Chaffee, an MD with almost 400,000 followers, said in an Instagram post.

And I almost choked on my broccoli when, while scrolling LinkedIn, I came across an interview with another doctor declaring that “there is zero scientific evidence to say that vegetables are required in the human diet.” That doctor, who described himself as “90% carnivore,” went on to say that all he’d eaten the previous day was a kilo of beef, and that vegetables have “anti-nutrients,” whatever they might be.

You don’t have to spend much time on social media to come across claims like this. The “traditionalist” influencer, author, and psychologist Jordan Peterson was promoting a meat-only diet as far back as 2018. A recent review of research into nutrition misinformation on social media found that the most diet information is shared on Instagram and YouTube, and that a lot of it is nonsense. So much so that the authors describe it as a “growing public health concern.”

What’s new is that some of this misinformation comes from the people who now lead America’s federal health agencies. In January Kennedy, who leads the Department of Health and Human Services, told a USA Today reporter that he was on a carnivore diet. “I only eat meat or fermented foods,” he said. He went on to say that the diet had helped him lose “40% of [his] visceral fat within a month.”

“Government needs to stop spreading misinformation that natural and saturated fats are bad for you,” Food and Drug Administration commissioner Martin Makary argued in a recent podcast interview. The principles of “whole foods and clean meats” are “biblical,” he said. The interviewer said that Makary’s warnings about pesticides made him want to “avoid all salads and completely miss the organic section in the grocery store.”

For the record: There’s plenty of evidence that a diet high in saturated fat can increase the risk of heart disease. That’s not government misinformation. 

The carnivore doctors’ suggestion to avoid vegetables is wrong too, says Gabby Headrick, associate director of food and nutrition policy at George Washington University’s Institute for Food Safety & Nutrition Security. There’s no evidence to suggest that a meat-only diet is good for you. “All of the nutrition science to date strongly identifies a wide array of vegetables … as being very health-promoting,” she adds.

To be fair to the influencers out there, diet is a tricky thing to study. Much of the research into nutrition relies on volunteers to keep detailed and honest food diaries—something that people are generally quite bad at. And the way our bodies respond to foods might be influenced by our genetics, our microbiomes, the way we prepare or consume those foods, and who knows what else.

Still, it will come as a surprise to no one that there is plenty of what the above study calls “low-quality content” floating around on social media. So it’s worth arming ourselves with a good dose of skepticism, especially when we come across posts that mention “miracle foods” or extreme, limited diets.

The truth is that most food is neither good nor bad when eaten in moderation. Diet trends come and go, and for most people, the best reasonable advice is simply to eat a balanced diet low in sugar, salt, and saturated fat. You know—the basics. No matter what that weird upside-down food pyramid implies. To the carnivore influencers, I say: get your misinformation off my broccoli.

This article first appeared in The Checkup, MIT Technology Review’s weekly biotech newsletter. To receive it in your inbox every Thursday, and read articles like this first, sign up here.

This week I want to tell you about an experimental surgical procedure that’s helping people have babies. Specifically, it’s helping people who have had treatment for bowel or rectal cancer.

Radiation and chemo can have pretty damaging side effects that mess up the uterus and ovaries. Surgeons are pioneering a potential solution: simply stitch those organs out of the way during cancer treatment. Once the treatment has finished, they can put the uterus—along with the ovaries and fallopian tubes—back into place.

It seems to work! Last week, a team in Switzerland shared news that a baby boy had been born after his mother had the procedure. Baby Lucien was the fifth baby to be born after the surgery and the first in Europe, says Daniela Huber, the gyno-oncologist who performed the operation. Since then, at least three others have been born, adds Reitan Ribeiro, the surgeon who pioneered the procedure. They told me the details.

Huber’s patient was 28 years old when a four-centimeter tumor was discovered in her rectum. Doctors at Sion Hospital in Switzerland, where Huber works, recommended a course of treatment that included multiple medications and radiotherapy—the use of beams of energy to shrink a tumor—before surgery to remove the tumor itself.

This kind of radiation can kill tumor cells, but it can also damage other organs in the pelvis, says Huber. That includes the ovaries and uterus. People who undergo these treatments can opt to freeze their eggs beforehand, but the harm caused to the uterus will mean they’ll never be able to carry a pregnancy, she adds. Damage to the lining of the uterus could make it difficult for a fertilized egg to implant there, and the muscles of the uterus are left unable to stretch, she says.

In this case, the woman decided that she did want to freeze her eggs. But it would have been difficult to use them further down the line—surrogacy is illegal in Switzerland.

Huber offered her an alternative.

She had been following the work of Ribeiro, a gynecologist oncologist formerly at the Erasto Gaertner Hospital in Curitiba, Brazil. There, Ribeiro had pioneered a new type of surgery that involved moving the uterus, fallopian tubes, and ovaries from their position in the pelvis and temporarily tucking them away in the upper abdomen, below the ribs.

Ribeiro and his colleagues published their first case report in 2017, describing a 26-year-old with a rectal tumor. (Ribeiro, who is now based at McGill University in Montreal, says the woman had been told by multiple doctors that her cancer treatment would destroy her fertility and had pleaded with him to find a way to preserve it.)

Huber remembers seeing Ribeiro present the case at a conference at the time. She immediately realized that her own patient was a candidate for the surgery, and that, as a surgeon who had performed many hysterectomies, she’d be able to do it herself. The patient agreed.

Huber’s colleagues at the hospital were nervous, she says. They’d never heard of the procedure before. “When I presented this idea to the general surgeon, he didn’t sleep for three days,” she tells me. After watching videos from Ribeiro’s team, however, he was convinced it was doable.

So before the patient’s cancer treatment was started, Huber and her colleagues performed the operation. The team literally stitched the organs to the abdominal wall. “It’s a delicate dissection,” says Huber, but she adds that “it’s not the most difficult procedure.” The surgery took two to three hours, she says. The stitches themselves were removed via small incisions around a week later. By that point, scar tissue had formed to create a lasting attachment.

The woman had two weeks to recover from the surgery before her cancer treatment began. That too was a success—within months, her tumor had shrunk so significantly that it couldn’t be seen on medical scans.

As a precaution, the medical team surgically removed the affected area of her colon. At the same time, they cut away the scar tissue holding the uterus, tubes, and ovaries in their new position and transferred the organs back into the pelvis.

Around eight months later, the woman stopped taking contraception. She got pregnant without IVF and had a mostly healthy pregnancy, says Huber. Around seven months into the pregnancy, there were signs that the fetus was not growing as expected. This might have been due to problems with the blood supply to the placenta, says Huber. Still, the baby was born healthy, she says.

Ribeiro says he has performed the surgery 16 times, and that teams in countries including the US, Peru, Israel, India, and Russia have performed it as well. Not every case has been published, but he thinks there may be around 40.

Since Baby Lucien was born last year, a sixth birth has been announced in Israel, says Huber. Ribeiro says he has heard of another two births since then, too. The most recent was to the first woman who had the procedure. She had a little girl a few months ago, he tells me.

No surgery is risk-free, and Huber points out there’s a chance that organs could be damaged during the procedure, or that a more developed cancer could spread. The uterus of one of Ribeiro’s patients failed following the surgery. Doctors are “still in the phase of collecting data to [create] a standardized procedure,” Huber says, but she hopes the surgery will offer more options to young people with some pelvic cancers. “I hope more young women could benefit from this procedure,” she says.

Ribeiro says the experience has taught him not to accept the status quo. “Everyone was saying … there was nothing to be done [about the loss of fertility in these cases],” he tells me. “We need to keep evolving and looking for different answers.”

This article first appeared in The Checkup, MIT Technology Review’s weekly biotech newsletter. To receive it in your inbox every Thursday, and read articles like this first, sign up here.

For the last couple of years, I’ve been following the progress of a group of individuals who believe death is humanity’s “core problem.” Put simply, they say death is wrong—for everyone. They’ve even said it’s morally wrong.

They established what they consider a new philosophy, and they called it Vitalism.

Vitalism is more than a philosophy, though—it’s a movement for hardcore longevity enthusiasts who want to make real progress in finding treatments that slow or reverse aging. Not just through scientific advances, but by persuading influential people to support their movement, and by changing laws and policies to open up access to experimental drugs.

And they’re starting to make progress.

Vitalism was founded by Adam Gries and Nathan Cheng—two men who united over their shared desire to find ways to extend human lifespan. I first saw Cheng speak back in 2023, at Zuzalu, a pop-up city in Montenegro for people who were interested in life extension and some other technologies. (It was an interesting experience—you can read more about it here.)

Zuzalu was where Gries and Cheng officially launched Vitalism. But I’ve been closely following the longevity scene since 2022. That journey took me to Switzerland, Honduras, and a compound in Berkeley, California, where like-minded longevity enthusiasts shared their dreams of life extension.

It also took me to Washington, DC, where, last year, supporters of lifespan extension presented politicians including Mehmet Oz, who currently leads the Centers for Medicare & Medicaid Services, with their case for changes to laws and policies.

The journey has been fascinating, and at times weird and even surreal. I’ve heard biohacking stories that ended with smoking legs. I’ve been told about a multi-partner relationship that might be made possible through the cryopreservation—and subsequent reanimation—of a man and the multiple wives he’s had throughout his life. I’ve had people tell me to my face that they consider themselves eugenicists, and that they believe that parents should select IVF embryos for their propensity for a long life.

I’ve seen people draw blood during dinner in an upscale hotel restaurant to test their biological age. I’ve heard wild plans to preserve human consciousness and resurrect it in machines. Others have told me their plans to inject men’s penises with multiple doses of an experimental gene therapy in order to treat erectile dysfunction and ultimately achieve “radical longevity.”

I’ve been shouted at and threatened with legal action. I’ve received barefoot hugs. One interviewee told me I needed Botox. It’s been a ride.

My reporting has also made me realize that the current interest in longevity reaches beyond social media influencers and wellness centers. Longevity clinics are growing in number, and there’s been a glut of documentaries about living longer or even forever.

At the same time, powerful people who influence state laws, giant federal funding budgets, and even national health policy are prioritizing the search for treatments that slow or reverse aging. The longevity community was thrilled when longtime supporter Jim O’Neill was made deputy secretary of health and human services last year. Other members of Trump’s administration, including Oz, have spoken about longevity too. “It seems that now there is the most pro-longevity administration in American history,” Gries told me.

I recently spoke to Alicia Jackson, the new director of ARPA-H. The agency, established in 2022 under Joe Biden’s presidency, funds “breakthrough” biomedical research. And it appears to have a new focus on longevity. Jackson previously founded and led Evernow, a company focused on “health and longevity for every woman.”

“There’s a lot of interesting technologies, but they all kind of come back to the same thing: Could we extend life years?” she told me over a Zoom call a few weeks ago. She added that her agency had “incredible support” from “the very top of HHS.” I asked if she was referring to Jim O’Neill. “Yeah,” she said. She wouldn’t go into the specifics.

Gries is right: There is a lot of support for advances in longevity treatments, and some of it is coming from influential people in positions of power. Perhaps the field really is poised for a breakthrough.

And that’s what makes this field so fascinating to cover. Despite the occasional weirdness.

This article first appeared in The Checkup, MIT Technology Review’s weekly biotech newsletter. To receive it in your inbox every Thursday, and read articles like this first, sign up here.

“Who here believes involuntary death is a good thing?” 

Nathan Cheng has been delivering similar versions of this speech over the last couple of years, so I knew what was coming. He was about to try to convince the 80 or so people in the audience that death is bad. And that defeating it should be humanity’s number one priority—quite literally, that it should come above all else in the social and political hierarchy.

“If you believe that life is good and there’s inherent moral value to life,” he told them, “it stands to reason that the ultimate logical conclusion here is that we should try to extend lifespan indefinitely.” 

Solving aging, he added, is “a problem that has an incredible moral duty for all of us to get involved in.”

It was the end of April, and the crowd—with its whoops and yeahs—certainly seemed convinced. They’d gathered at a compound in Berkeley, California, for a three-day event called the Vitalist Bay Summit. It was part of a longer, two-month residency (simply called Vitalist Bay) that hosted various events to explore tools—from drug regulation to cryonics—that might be deployed in the fight against death. One of the main goals, though, was to spread the word of Vitalism, a somewhat radical movement established by Cheng and his colleague Adam Gries a few years ago.

No relation to the lowercase vitalism of old, this Vitalism has a foundational philosophy that’s deceptively simple: to acknowledge that death is bad and life is good. The strategy for executing it, though, is far more obviously complicated: to launch a longevity revolution. 

Interest in longevity has certainly taken off in recent years, but as the Vitalists see it, it has a branding problem. The term “longevity” has been used to sell supplements with no evidence behind them, “anti-aging” has been used by clinics to sell treatments, and “transhumanism” relates to ideas that go well beyond the scope of defeating death. Not everyone in the broader longevity space shares Vitalists’ commitment to actually making death obsolete. As Gries, a longtime longevity devotee who has largely become the enthusiastic public face of Vitalism, said in an online presentation about the movement in 2024, “We needed some new word.”

“Vitalism” became a clean slate: They would start a movement to defeat death, and make that goal the driving force behind the actions of individuals, societies, and nations. Longevity could no longer be a sideshow. For Vitalism to succeed, budgets would need to change. Policy would need to change. Culture would need to change. Consider it longevity for the most hardcore adherents—a sweeping mission to which nothing short of total devotion will do.

“The idea is to change the systems and the priorities of society at the highest levels,” Gries said in the presentation.

To be clear, the effective anti-aging treatments the Vitalists are after don’t yet exist. But that’s sort of the point: They believe they could exist if Vitalists are able to spread their gospel, influence science, gain followers, get cash, and ultimately reshape government policies and priorities. 

For the past few years, Gries and Cheng have been working to recruit lobbyists, academics, biotech CEOs, high-net-worth individuals, and even politicians into the movement, and they’ve formally established a nonprofit foundation “to accelerate Vitalism.” Today, there’s a growing number of Vitalists (some paying foundation members, others more informal followers, and still others who support the cause but won’t publicly admit as much), and the foundation has started “certifying” qualifying biotech companies as Vitalist organizations. Perhaps most consequentially, Gries, Cheng, and their peers are also getting involved in shaping US state laws that make unproven, experimental treatments more accessible. They hope to be able to do the same at the national level.

Vitalism cofounders Nathan Cheng and Adam Gries want to launch a longevity revolution.

All this is helping Vitalists grow in prominence, if not also power. In the past, people who have spoken of living forever or making death “optional” have been dismissed by their academic colleagues. I’ve been covering the broader field of aging science for a decade, and I’ve seen scientists roll their eyes, shrug their shoulders, and turn their backs on people who have talked this way. That’s not the case for the Vitalists.  

Even the scientists who think that Vitalist ideas of defeating death are wacky, unattainable ones, with the potential to discredit their field, have shown up on stage with Vitalism’s founders, and these serious researchers provide a platform for them at more traditionally academic events.

I saw this collegiality firsthand at Vitalist Bay. Faculty members from Harvard, Stanford, and the University of California, Berkeley, all spoke at events. Eric Verdin, the prominent researcher who directs the Buck Institute for Research on Aging in Novato, California, had also planned to speak, although a scheduling clash meant he couldn’t make it in the end. “I have very different ideas in terms of what’s doable,” he told me. “But that’s part of the [longevity] movement—there’s freedom for people to say whatever they want.” 

Many other well-respected scientists attended, including representatives of ARPA-H, the US federal agency for health research and breakthrough technologies. And as I left for a different event on longevity in Washington, DC, just after the Vitalist Bay Summit, a sizable group of Vitalist Bay attendees headed that way too, to make the case for longevity to US lawmakers.

The Vitalists feel that momentum is building, not just for the science of aging and the development of lifespan-extending therapies, but for the acceptance of their philosophy that defeating death should be humanity’s top concern. 

This, of course, sparks some pretty profound questions. What would a society without death look like—and would we even want it? After all, death has become an important part of human culture the world over. And even if Vitalists aren’t destined to realize their lofty goal, their growing influence could still have implications for us all. As they run more labs and companies, and insert themselves into the making of laws and policy, perhaps they will discover treatments that really do slow or even reverse aging. In the meantime, though, some ethicists are concerned that experimental and unproven medicines—including potentially dangerous ones—are becoming more accessible, in some cases with little to no oversight. 

Gries, ultimately, has a different view of the ethics here. He thinks that being “okay with death” is what disqualifies a person from being considered ethical. “Death is just wrong,” he says. “It’s not just wrong for some people. It’s wrong for all people.”

The birth of a revolution

When I arrived at the Vitalist Bay Summit on April 25, I noticed that the venue was equipped with everything a longevity enthusiast might need: napping rooms, a DEXA body-composition scanner, a sauna in a bus, and, for those so inclined, 24-hour karaoke. 

I was told that around 300 people had signed up for that day’s events, which was more than had attended the previous week. That might have been because arguably the world’s most famous longevity enthusiast, Bryan Johnson, was about to make an appearance. (If you’re curious to know more about what Johnson was doing there, you can read about our conversation here.) 

The key to Vitalism has always been that “death is humanity’s core problem, and aging its primary agent,” cofounder Adam Gries told me. “So it was, and so it has continued, as it was foretold.” 

But Gries, another man in his 40s who doesn’t want to die, was the first to address the audience that day. Athletic and energetic, he bounded across a stage wearing bright yellow shorts and a long-sleeved shirt imploring people to “Choose Life: VITALISM.”

Gries is a tech entrepreneur who describes himself as a self-taught software engineer who’s “good at virality.” He’s been building companies since he was in college in the 2000s, and grew his personal wealth by selling them.

As with many other devotees to the cause, his deep interest in life extension was sparked by Aubrey de Grey, a controversial researcher with an iconic long beard and matching ponytail. He’s known widely both for his optimistic views about “defeating aging” and for having reportedly made sexual comments to two longevity entrepreneurs. (In an email, de Grey said he’s “never disputed” one of these remarks but denied having made the other. “My continued standing within the longevity community speaks for itself,” he added.) 

In an influential 2005 TED Talk (which has over 4.8 million views), de Grey predicted that people would live to 1,000 and spoke of the possibility of new technologies that would continue to stave off death, allowing some to avoid it indefinitely. (In a podcast recorded last year, Cheng described a recording of this talk as “the OG longevity-pilling YouTube video.”)

“It was kind of evident to me that life is great,” says Gries. “So I’m kind of like, why would I not want to live?”

A second turning point for Gries came during the early stages of the covid-19 pandemic, when he essentially bet against companies that he thought would collapse. “I made this 50 [fold] return,” he says. “It was kind of like living through The Big Short.”

Gries and his wife fled from San Francisco to Israel, where he grew up, and later traveled to Taiwan, where he’d obtained a “golden visa” and which was, at the time, one of only two countries that had not reported a single case of covid. His growing wealth afforded him the opportunity to take time from work and think about the purpose of life. “My answer was: Life is the purpose of life,” he says. He didn’t want to die. He didn’t want to experience the “journey of decrepitude” that aging often involves.

So he decided to dedicate himself to the longevity cause. He went about looking up others who seemed as invested as he was. In 2021 his search led him to Cheng, a Chinese-Canadian entrepreneur based in Toronto. He had dropped out of a physics PhD a few years earlier after experiencing what he describes on his website as “a massive existential crisis” and shifted his focus to “radical longevity.” (Cheng did not respond to email requests for an interview.)

The pair “hit it off immediately,” says Gries, and they spent the following two years trying to figure out what they could do. The solution they finally settled on: revolution.

After all, Gries reasons, that’s how significant religious and social movements have happened in the past. He says they sought inspiration from the French and American Revolutions, among others. The idea was to start with some kind of “enlightenment,” and with a “hardcore group,” to pursue significant social change with global ramifications. 

“We were convinced that without a revolution,” Gries says, “we were as good as dead.” 

A home for believers

Early on, they wrote a Vitalist declaration, a white paper that lists five core statements for believers:

1. Life and health are good. Death is humanity’s core problem, and aging its primary agent.
2. Aging causes immense suffering, and obviating aging is scientifically plausible.
3. Humanity should apply the necessary resources to reach freedom from aging as soon as possible.
4. I will work on or support others to work on reaching unlimited healthy human lifespan.
5. I will carry the message against aging and death.

While it’s not an explicit part of the manifesto, it was important to them to think about it as a moral philosophy as well as a movement. As Cheng said at the time, morality “guides most of the actions of our lives.” The same should be true of Vitalism, he suggested. 

Gries has echoed this idea. The belief that “death is morally bad” is necessary to encourage behavior change, he told me in 2024. It is a moral drive, or moral purpose, that pushes people to do difficult things, he added.

Revolution, after all, is difficult. And to succeed—to “get unlimited great health to the top of the priority list,” as Gries says—the movement would need to infiltrate the government and shape policy decisions and national budgets. The Apollo program got people to the moon with less than 1% of US GDP; imagine, Gries asks, what we could do to human longevity with a mere 1% of GDP?

It makes sense, then, that Gries and Cheng launched Vitalism in 2023 at Zuzalu, a “pop-up city” in Montenegro that provided a two-month home for like-minded longevity enthusiasts. The gathering was in some ways a loose prototype for what they wanted to accomplish. Cheng spoke there of how they wanted to persuade 10,000 or so Vitalists to move to Rhode Island. Not only was it close to the biotech hub of Boston, but they believed it had a small enough population for an influx of new voters sharing their philosophy to influence local and state elections. “Five to ten thousand people—that’s all we need,” he said. Or if not Rhode Island, another small-ish US state, where they could still change state policy from the inside. 

The ultimate goal was to recruit Vitalists to help them establish a “longevity state”—a recognized jurisdiction that “prioritizes doing something about aging,” Cheng said, perhaps by loosening regulations on clinical trials or supporting biohacking.

This idea is popular among many vocal members of the Vitalism community. It borrows from the concept of the “network state” developed by former Coinbase CTO Balaji Srinivasan, defined as a new city or country that runs on cryptocurrency; focuses on a goal, in this case extending human lifespan; and “eventually gains diplomatic recognition from preexisting states.” 

Some people not interested in dying have made progress toward realizing such a domain. Following the success of Zuzalu, one of the event’s organizers, Laurence Ion, a young cryptocurrency investor and self-proclaimed Vitalist, joined a fellow longevity enthusiast named Niklas Anzinger to organize a sequel in Próspera, the private “special economic zone” on the Honduran island of Roatán. They called their “pop-up city” Vitalia.

I visited shortly after it launched in January 2024. The goal was to create a low-regulation biotech hub to fast-track the development of anti-aging drugs, though the “city” was more like a gated resort that hosted talks from a mix of respected academics, biohackers, biotech CEOs, and straight-up eugenicists. There was a strong sense of community—many attendees were living with or near each other, after all. A huge canvas where attendees could leave notes included missives like “Don’t die,” “I love you,” and “Meet technoradicals building the future!” 

But Vitalia was short-lived, with events ending by the start of March 2024. And while many of the vibes were similar to what I’d later see at Vitalist Bay, the temporary nature of Vitalia didn’t quite match the ambition of Gries and Cheng. 

Patri Friedman, a 49-year-old libertarian and grandson of the economist Milton Friedman who says he attended Zuzalu, Vitalia, and Vitalist Bay, envisions something potentially even bolder. He’s the founder of the Seasteading Institute, which has the goal of “building startup communities that float on the ocean with any measure of political autonomy” and has received funding and support from the billionaire Peter Thiel. Friedman also founded Pronomos Capital, a venture capital fund that invests in projects focused on “building the cities of tomorrow.” 

His company is exploring various types of potential network states, but he says he’s found that medical tourism—and, specifically, a hunger for life extension—dominates the field. “People do not want this ‘10 years and a billion dollars to pass a drug’ thing with the FDA,” says Friedman. (While he doesn’t call himself a Vitalist, partly because he’s “almost never going to agree with” any kind of decree, Friedman holds what you might consider similarly staunch sentiments about death, which he referred to as “murder by omission.” When I asked him if he has a target age he’d like to reach, he told me he found the question “mind-bogglingly strange” and “insane.” “How could you possibly be like: Yes, please murder me at this time?” he replied. “I can always fucking shoot myself in the head—I don’t need anybody’s help.”) 

But even as Vitalists and those aligned with their beliefs embrace longevity states, Gries and Cheng are reassessing their former ambitions. The network-state approach has limits, Gries tells me. And encouraging thousands of people to move to Rhode Island wasn’t as straightforward as they’d hoped it might be.

Not because he can’t find tens of thousands of Vitalists, Gries stresses—but most of them are unwilling to move their lives for the sake of influencing the policy of another state. He compares Vitalism to a startup, with a longevity state as its product. For the time being, at least, there isn’t enough consumer appetite for that product, he says. 

The past year shows that it may in fact be easier to lobby legislators in states that are already friendly to deregulation. Anzinger and a lobbying group called the Alliance for Longevity Initiatives (A4LI) were integral to making Montana the first US hub for experimental medical treatments, with a new law to allow clinics to sell experimental therapies once they have been through preliminary safety tests (which don’t reveal whether a drug actually works). But Gries and his Vitalist colleagues also played a role—“providing feedback, talking to lawmakers … brainstorming [and] suggesting ideas,” Gries says. 

The Vitalist crew has been in conversation with lawmakers in New Hampshire, too. In an email in December, Gries and Cheng claimed they’d “helped to get right-to-try laws passed” in the state—an apparent reference to the recent expansion of a law to make more unapproved treatments accessible to people with terminal illnesses. Meanwhile, three other bills that expand access even further are under consideration. 

Ultimately, Gries stresses, Vitalism is “agnostic to the fixing strategies” that will help them meet their goals. There is, though, at least one strategy he’s steadfast about: building influence.

Only the hardcore 

To trigger a revolution, the Vitalists may need to recruit only around 3% or 4% of “society” to their movement, Gries believes. (Granted, that does still mean hundreds of millions of people.) “If you want people to take action, you need to focus on a small number of very high-leverage people,” he tells me. 

That, perhaps unsurprisingly, includes wealthy individuals with “a net worth of $10 million or above,” he says. He wants to understand why (with some high-profile exceptions, including Thiel, who has been investing in longevity-related companies and foundations for decades) most uber-wealthy people don’t invest in the field—and how he might persuade them to do so. He won’t reveal the names of anyone he’s having conversations with. 

These “high-leverage” people might also include, Gries says, well-respected academics, leaders of influential think tanks, politicians and policymakers, and others who work in government agencies.

A revolution needs to find its foot soldiers. And at the most basic level, that will mean boosting the visibility of the Vitalism brand—partly through events like Vitalist Bay, but also by encouraging others, particularly in the biotech space, to sign on. Cheng talks of putting out a “bat signal” for like-minded people, and he and Gries say that Vitalism has brought together people who have gone on to collaborate or form companies. 

There’s also their nonprofit Vitalism International Foundation, whose supporters can opt to become “mobilized Vitalists” with monthly payments of $29 or more, depending on their level of commitment. In addition, the foundation works with longevity biotech companies to recognize those that are “aligned” with its goals as officially certified Vitalist organizations. “Designation may be revoked if an organization adopts apologetic narratives that accept aging or death,” according to the website. At the time of writing, that site lists 16 certified Vitalist organizations, including cryopreservation companies, a longevity clinic, and several research companies. 

One of them is Shift Bioscience, a company using CRISPR and aging clocks—which attempt to measure biological age—to identify genes that might play a significant role in the aging process and potentially reverse it. It says it has found a single gene that can rejuvenate multiple types of cells. 

Shift cofounder Daniel Ives, who holds degrees in mitochondrial and computational biology, tells me he was also won over to the longevity cause by de Grey’s 2005 TED Talk. He now has a countdown on his computer: “It’s my days till death,” he says—around 22,000 days left. “I’m using that to keep myself focused.” 

Ives calls himself the “Vitalist CEO” of Shift Bioscience. He thinks the label is important first as a way for like-minded people to find and support each other, grow their movement, and make the quest for longevity mainstream. Second, he says, it provides a way to appeal to “hardcore” lifespan extensionists, given that others in the wellness and cosmetics industry have adopted the term “longevity” without truly applying themselves to finding rejuvenation therapies. He refers to unnamed companies and individuals who claim that drinking juices, for example, can reverse aging by five years or so.

“You don’t have to convince the mainstream,” says Mark Hamalainen, a contributor to the Vitalism white paper. Though “kind of a terrible example,” he notes, Stalinism started small. “Sometimes you just have to convince the right people.”

“Somebody will make these claims and basically throw legitimate science under the bus,” he says. He doesn’t want spurious claims made on social media to get lumped in with the company’s serious molecular biology. Shift’s head of machine learning, Lucas Paulo de Lima Camillo, was recently awarded a $10,000 prize by the well-respected Biomarkers of Aging Consortium for an aging clock he developed. 

Another out-and-proud Vitalist CEO is Anar Isman, the cofounder of AgelessRx, a telehealth provider that offers prescriptions for purported longevity drugs—and a certified Vitalist organization. (Isman, who is in his early 40s, used to work at a hedge fund but was inspired to join the longevity field by—you guessed it—de Grey.)

During a panel session at Vitalist Bay, he stressed that he too saw longevity as a movement—and a revolution—rather than an industry. But he also claimed his company wasn’t doing too badly commercially. “We’ve had a lot of demand,” he said. “We’ve got $60 million plus in annual revenue.”

Many of his customers come to the site looking for treatments for specific ailments, he tells me. He views each as an opportunity to “evangelize” his views on “radical life extension.” “I don’t see a difference between … dying tomorrow or dying in 30 years,” he says. He wants to live “at least 100 more” years.

Vitalism, though, isn’t just appealing to commercial researchers. Mark Hamalainen, a 41-year-old science and engineering advisor at ARPA-H, describes himself as a Vitalist. He says he “kind of got roped into” Vitalism because he also works with Cheng—they founded the Longevity Biotech Fellowship, which supports new entrants to the field through mentoring programs. “I kind of view it as a more appealing rebranding of some of the less radical aspects of transhumanism,” he says. Transhumanism—the position that we can use technologies to enhance humans beyond the current limits of biology—covers a broad terrain, but “Vitalism is like: Can we just solve this death thing first? It’s a philosophy that’s easy to get behind.”

In government, he works with individuals like Jean Hébert, a former professor of genetics and neuroscience who has investigated the possibility of rejuvenating the brain by gradually replacing parts of it; Hébert has said that “[his] mission is to beat aging.” He spoke at Zuzalu and Vitalist Bay. 

Andrew Brack, who serves as the program manager for proactive health at ARPA-H, was at Vitalist Bay, too. Both Brack and Hébert oversee healthy federal budgets—Hébert’s brain replacement project was granted $110 million in 2024, for example.

Neither Hébert nor Brack has publicly described himself as a Vitalist, and Hébert wouldn’t agree to speak to me without the approval of ARPA-H’s press office, which didn’t respond to multiple requests for an interview with him or Brack. Brack did not respond to direct requests for an interview.

Gries says he thinks that “many people at [the US Department of Health and Human Services], including all agencies, have a longevity-positive view and probably agree with a lot of the ideas Vitalism stands for.” And he is hoping to help secure federal positions for others who are similarly aligned with his philosophy. On both Christmas Eve and New Year’s Eve last year, Gries and Cheng sent fundraising emails describing an “outreach effort” to find applicants for six open government positions that, together, would control billions of dollars in federal funding. “Qualified, mission-aligned candidates we’d love to support do exist, but they need to be found and encouraged to apply,” the pair wrote in the second email. “We’re starting a systematic search to reach, screen, and support the best candidates.” 

Hamalainen supports Gries’s plan to target high-leverage individuals. “You don’t have to convince the mainstream,” he says. Though “kind of a terrible example,” Hamalainen notes, Stalinism started small. “Sometimes you just have to convince the right people.”

One of the “right” people may be the man who inspired Gries, Hamalainen, Ives, Isman, and so many others to pursue longevity in the first place: de Grey. He’s now a paid-up Vitalist and even spoke at Vitalist Bay. Having been in the field for over 20 years, de Grey tells me, he’s seen various terms fall in and out of favor. Those terms now have “baggage that gets in the way,” he says. “Sometimes it’s useful to have a new term.”

The sometimes quiet (sometimes powerful, sometimes influential) Vitalists

Though one of the five principles of Vitalism is a promise to “carry the message,” some people who agree with its ideas are reluctant to go public, including some signed-up Vitalists. I’ve asked Gries multiple times over several years, but he won’t reveal how many Vitalists there are, let alone who makes up the membership.

Even some of the founders of Vitalism don’t want to be public about it. Around 30 people were involved in developing the movement, Gries says—but only 22 are named as contributors to the Vitalism white paper (with Gries as its author), including Cheng, Vitalia’s Ion, and ARPA-H’s Hamalainen. Gries won’t reveal the names of the others. He acknowledges that some people just don’t like to publicly affiliate with any organization. That’s certainly what I’ve found when I’ve asked members of the longevity community if they’re Vitalists. Many said they agreed with the Vitalist declaration, and that they liked and supported what Gries was doing. But they didn’t want the label.

Some people worry that associating with a belief system that sounds a bit religious—even cult-like, some say—won’t do the cause any favors. Others have a problem with the specific wording of the declaration.

For instance, Anzinger—the other Vitalia founder—won’t call himself a Vitalist. He says he respects the mission, but that the declaration is “a bit poetic” for his liking.

And Dylan Livingston, CEO of A4LI and arguably one of the most influential longevity enthusiasts out there, won’t describe himself as a Vitalist either.

Many other longevity biotech CEOs also shy away from the label—including Emil Kendziorra, who runs the human cryopreservation company Tomorrow Bio, even though that’s a certified Vitalist organization. Kendziorra says he agrees with most of the Vitalist declaration but thinks it is too “absolutist.” He also doesn’t want to imply that the pursuit of longevity should be positioned above war, hunger, and other humanitarian issues. (Gries has heard this argument before, and counters that both the vast spending on health care for people in the last years of their life and the use of lockdown strategies during the covid pandemic suggest that, deep down, lifespan extension is “society’s revealed preference.”)

Still, because Kendziorra agrees with almost everything in the declaration, he believes that “pushing it forward” and bringing more attention to the field by labeling his company a Vitalist organization is a good thing. “It’s to support other people who want to move the world in that direction,” he says. (He also offered Vitalist Bay attendees a discount on his cryopreservation services.) 

“There’s a lot of closeted scientists working in our field, and they get really excited about lifespans increasing,” explains Ives of Shift Bioscience. “But you’ll get people who’ll accuse you of being a lunatic that wants to be immortal.” He claims that people who represent biotech companies tell him “all the time” that they are secretly longevity companies but avoid using the term because they don’t want funders or collaborators to be “put off.”

Ultimately, it may not really matter how much people adopt the Vitalist label as long as the ideas break through. “It’s pretty simple. [The Vitalist declaration] has five points—if you agree with the five points, you are a Vitalist,” says Hamalainen. “You don’t have to be public about it.” He says he’s spoken to others about “coming out of the closet” and that it’s been going pretty well. 

Gries puts it more bluntly: “If you agree with the Vitalist declaration, you are a Vitalist.” 

And he hints that there are now many people in powerful positions—including in the Trump administration—who share his views, even if they don’t openly identify as Vitalists. 

For Gries, this includes Jim O’Neill, the deputy secretary of health and human services, whom I profiled a few months after he became Robert F. Kennedy Jr.’s number two. (More recently, O’Neill was temporarily put in charge of the US Centers for Disease Control and Prevention.)

O’Neill has long been interested in both longevity and the idea of creating new jurisdictions. Until March 2024, he served on the board of directors of Friedman’s Seasteading Institute. He also served as CEO of the SENS Research Foundation, a longevity organization founded by de Grey, between 2019 and 2021, and he represented Thiel as a board member there for many years. Many people in the longevity community say they know him personally, or have at least met him. (Tristan Roberts, a biohacker who used to work with a biotech company operating in Próspera, tells me he served O’Neill gin when he visited his Burning Man camp, which he describes as a “technology gay camp from San Francisco and New York.” Hamalainen also recalls meeting O’Neill at Burning Man, at a “techy, futurist” camp.) (Neither O’Neill nor representatives from the Department of Health and Human Services responded to a request to comment about this.)

O’Neill’s views are arguably becoming less fringe in DC these days. The day after the Vitalist Bay Summit, A4LI was hosting its own summit in the capital with the goal of “bringing together leaders, advocates, and innovators from around the globe to advance legislative initiatives that promote a healthier human lifespan.” I recognized lots of Vitalist Bay attendees there, albeit in more formal attire.

The DC event took place over three days in late April. The first two involved talks by longevity enthusiasts across the spectrum, including scientists, lawyers, and biotech CEOs. Vitalia’s Anzinger spoke about the success he’d had in Próspera, and ARPA-H’s Brack talked about work his agency was doing. (Hamalainen was also there, although he said he was not representing ARPA-H.)

But the third day was different and made me think Gries may be right about Vitalism’s growing reach. It began with a congressional briefing on Capitol Hill, during which Representative Gus Bilirakis, a Republican from Florida, asked, “Who doesn’t want to live longer, right?” As he explained, “Longevity science … directly aligns with the goals of the Make America Healthy Again movement.”

“There’s a lot of closeted scientists working in our field, and they get really excited about lifespans increasing,” says Daniel Ives of Shift Bioscience. “But you’ll get people who’ll accuse you of being a lunatic that wants to be immortal.”

Bilirakis and Representative Paul Tonko, a New York Democrat, were followed by Mehmet Oz, the former TV doctor who now leads the Centers for Medicare and Medicaid Services; he opened with typical MAHA talking points about chronic disease and said US citizens have a “patriotic duty” to stay healthy to keep medical costs down. The audience was enthralled as Oz talked about senescent cells, the zombie-like aged cells that are thought to be responsible for some age-related damage to organs and tissues. (The offices of Bilirakis and Tonko did not respond to a request for comment; neither did the Centers for Medicare and Medicaid Services.)

And while none of the speakers went anywhere near the concept of radical life extension, the Vitalists in the audience were suitably encouraged. 

Gries is too: “It seems that now there is the most pro-longevity administration in American history.” 

The fate of “immortality quests”

Whether or not Vitalism starts a revolution, it will almost always be controversial in some quarters. While believers see an auspicious future, others are far less certain of the benefits of a world designed to defeat death.

Gries and Cheng often make the case for deregulation in their presentations. But ethicists—and even some members of the longevity community—point out that this comes with risks. Some question whether it is ever ethical to sell a “treatment” without some idea of how likely it is to benefit the person buying and taking it. Enthusiasts counter with arguments about bodily autonomy. And they hope Montana is just the start. 

Then there’s the bigger picture. Is it really that great not to die … ever? Some ethicists argue that for many cultures, death is what gives meaning to life. 

Sergio Imparato, a moral philosopher and medical ethicist at Harvard University, believes that death itself has important moral meaning. We know our lives will end, and our actions have value precisely because our time is limited, he says. Imparato is concerned that Vitalists are ultimately seeking to change what it means to be human—a decision that should involve all members of society. 

Alberto Giubilini, a philosopher at the University of Oxford, agrees. “Death is a defining feature of humanity,” he says. “Our psychology, our cultures, our rituals, our societies, are built around the idea of coping with death … it’s part of human nature.”

Imparato’s family is from Naples, Italy, where poor residents were once laid to rest in shared burial sites, with no headstones to identify them. He tells me how the locals came to visit, clean, and even “adopt” the skulls as family members. It became a weekly ritual for members of the community, including his grandmother, who was a young girl at the time. “It speaks to what I consider the cultural relevance of death,” he says. “It’s the perfect counterpoint to … the Vitalist conception of life.”  

Gries seems aware of the stigma around such “immortality quests,” as Imparato calls them. In his presentations, Gries shares lists of words that Vitalists should try to avoid—like “eternity,” “radical,” and “forever,” as well as any religious terms. 

He also appears to be dropping, at least publicly, the idea that Vitalism is a “moral” movement. Morality was “never part of the Vitalist declaration,” Gries told me in September. When I asked him why he had changed his position on this, he dismissed the question. “Our point … was always that death is humanity’s core problem, and aging its primary agent,” he told me. “So it was, and so it has continued, as it was foretold.” 

But despite these attempts to tweak and control the narrative, Vitalism appears to be opening the door to an incredibly wide range of sentiments in longevity science. A decade ago, I don’t think there would have been any way that the views espoused by Gries, Anzinger, and others who support Vitalist sentiments would have been accepted by the scientific establishment. After all, these are people who publicly state they hope to live indefinitely and who have no training in the science of aging, and who are open about their aims to find ways to evade the restrictions set forth by regulatory agencies like the FDA—all factors that might have rendered them outcasts not that long ago.

But Gries and peers had success in Montana. Influential scientists and policymakers attend Vitalism events, and Vitalists are featured regularly at more mainstream longevity events. Last year’s Aging Research and Drug Discovery (ARDD) conference in Copenhagen—widely recognized as the most important meeting in aging science—was sponsored in part by Anzinger’s new Próspera venture, Infinita City, as well as by several organizations that are either certified Vitalist or led by Vitalists.

“I was thinking that maybe what I was doing was very fringe or out there,” Anzinger, the non-Vitalist supporter of Vitalism, admits. “But no—I feel … loads of support.”

There was certainly an air of optimism at the Vitalist Bay Summit in Berkeley. Gries’s positivity is infectious. “All the people who want a fun and awesome surprise gift, come on over!” he called out early on the first day. “Raise your voice if you’re excited!” The audience whooped in response. He then proceeded to tell everyone, Oprah Winfrey–style, that they were all getting a free continuous glucose monitor. “You get a CGM! You get a CGM!” Plenty of attendees actually attached them to their arms on the spot.

Every revolution has to start somewhere, right?

This piece has been updated to clarify a quote from Mark Hamalainen.

When Elon Musk was at Davos last week, an interviewer asked him if he thought aging could be reversed. Musk said he hasn’t put much time into the problem but suspects it is “very solvable” and that when scientists discover why we age, it’s going to be something “obvious.”

Not long after, the Harvard professor and life-extension evangelist David Sinclair jumped into the conversation on X to strongly agree with the world’s richest man. “Aging has a relatively simple explanation and is apparently reversible,” wrote Sinclair. “Clinical Trials begin shortly.”

“ER-100?” Musk asked.

“Yes” replied Sinclair.

ER-100 turns out to be the code name of a treatment created by Life Biosciences, a small Boston startup that Sinclair cofounded and which he confirmed today has won FDA approval to proceed with the first targeted attempt at age reversal in human volunteers. 

The company plans to try to treat eye disease with a radical rejuvenation concept called “reprogramming” that has recently attracted hundreds of millions in investment for Silicon Valley firms like Altos Labs, New Limit, and Retro Biosciences, backed by many of the biggest names in tech. 

The technique attempts to restore cells to a healthier state by broadly resetting their epigenetic controls—switches on our genes that determine which are turned on and off.  

“Reprogramming is like the AI of the bio world. It’s the thing everyone is funding,” says Karl Pfleger, an investor who backs a smaller UK startup, Shift Bioscience. He says Sinclair’s company has recently been seeking additional funds to keep advancing its treatment.

Reprogramming is so powerful that it sometimes creates risks, even causing cancer in lab animals, but the version of the technique being advanced by Life Biosciences passed initial safety tests in animals.

But it’s still very complex. The trial will initially test the treatment on about a dozen patients with glaucoma, a condition where high pressure inside the eye damages the optic nerve. In the tests, viruses carrying three powerful reprogramming genes will be injected into one eye of each patient, according to a description of the study first posted in December. 

To help make sure the process doesn’t go too far, the reprogramming genes will be under the control of a special genetic switch that turns them on only while the patients take a low dose of the antibiotic doxycycline. Initially, they will take the antibiotic for about two months while the effects are monitored. 

Executives at the company have said for months that a trial could begin this year, sometimes characterizing it as a starting bell for a new era of age reversal. “It’s an incredibly big deal for us as an industry,” Michael Ringel, chief operating officer at Life Biosciences, said at an event this fall. “It’ll be the first time in human history, in the millennia of human history, of looking for something that rejuvenates … So watch this space.”

The technology is based on the Nobel Prize–winning discovery, 20 years ago, that introducing a few potent genes into a cell will cause it to turn back into a stem cell, just like those found in an early embryo that develop into the different specialized cell types. These genes, known as Yamanaka factors, have been likened to a “factory reset” button for cells. 

But they’re dangerous, too. When turned on in a living animal, they can cause an eruption of tumors.

That is what led scientists to a new idea, termed “partial” or “transient” reprogramming. The idea is to limit exposure to the potent genes—or use only a subset of them—in the hope of making cells act younger without giving them complete amnesia about what their role in the body is.

Not all scientists agree that reprogramming really counts as age reversal. But Sinclair has doubled down. He’s been advancing the theory that the gradual loss of correct epigenetic information in our cells is, in fact, the ultimate cause of aging—just the kind of root cause that Musk was alluding to.

“Elon does seem to be paying attention to the field and [is] seemingly in sync with [my theory],” Sinclair said in an email.

Reprogramming isn’t the first longevity fix championed by Sinclair, who’s written best-selling books and commands stratospheric fees on the longevity lecture circuit. Previously, he touted the longevity benefits of molecules called sirtuins as well as resveratrol, a molecule found in red wine. But some critics say he greatly exaggerates scientific progress, pushback that culminated in a 2024 Wall Street Journal story that dubbed him a “reverse-aging guru” whose companies “have not panned out.” 

Life Biosciences has been among those struggling companies. Initially formed in 2017, it at first had a strategy of launching subsidiaries, each intended to pursue one aspect of the aging problem. But after these made limited progress, in 2021 it hired a new CEO, Jerry McLaughlin, who has refocused its efforts  on Sinclair’s mouse vision results and the push toward a human trial. 

The company has discussed the possibility of reprogramming other organs, including the brain. And Ringel, like Sinclair, entertains the idea that someday even whole-body rejuvenation might be feasible. But for now, it’s better to think of the study as a proof of concept that’s still far from a fountain of youth. “The optimistic case is this solves some blindness for certain people and catalyzes work in other indications,” says Pfleger, the investor. “It’s not like your doctor will be writing a prescription for a pill that will rejuvenate you.”

Life’s treatment also relies on an antibiotic switching mechanism that, while often used in lab animals, hasn’t been tried in humans before. Since the switch is built from gene components taken from E. coli and the herpes virus, it’s possible that it could cause an immune reaction in humans, scientists say. 

“I was always thinking that for widespread use you might need a different system,” says Noah Davidsohn, who helped Sinclair implement the technique and is now chief scientist at a different company, Rejuvenate Bio. And Life’s choice of reprogramming factors—it’s picked three, which go by the acronym OSK—may also be risky. They are expected to turn on hundreds of other genes, and in some circumstances the combination can cause cells to revert to a very primitive, stem-cell-like state.

Other companies studying reprogramming say their focus is on researching which genes to use, in order to achieve time reversal without unwanted side effects. New Limit, which has been carrying out an extensive search for such genes, says it won’t be ready for a human study for two years. At Shift, experiments on animals are only beginning now.

“Are their factors the best version of rejuvenation? We don’t think they are. I think they are working with what they’ve got,” Daniel Ives, the CEO of Shift, says of Life Biosciences. “But I think they’re way ahead of anybody else in terms of getting into humans. They have found a route forward in the eye, which is a nice self-contained system. If it goes wrong, you’ve still got one left.”

This week marked a rather unpleasant anniversary: It’s a year since Texas reported a case of measles—the start of a significant outbreak that ended up spreading across multiple states. Since the start of January 2025, there have been over 2,500 confirmed cases of measles in the US. Three people have died.

As vaccination rates drop and outbreaks continue, scientists have been experimenting with new ways to quickly identify new cases and prevent the disease from spreading. And they are starting to see some success with wastewater surveillance.

After all, wastewater contains saliva, urine, feces, shed skin, and more. You could consider it a rich biological sample. Wastewater analysis helped scientists understand how covid was spreading during the pandemic. It’s early days, but it is starting to help us get a handle on measles.

Globally, there has been some progress toward eliminating measles, largely thanks to vaccination efforts. Such efforts led to an 88% drop in measles deaths between 2000 and 2024, according to the World Health Organization. It estimates that “nearly 59 million lives have been saved by the measles vaccine” since 2000.

Still, an estimated 95,000 people died from measles in 2024 alone—most of them young children. And cases are surging in Europe, Southeast Asia, and the Eastern Mediterranean region.

Last year, the US saw the highest levels of measles in decades. The country is on track to lose its measles elimination status—a sorry fate that met Canada in November after the country recorded over 5,000 cases in a little over a year.

Public health efforts to contain the spread of measles—which is incredibly contagious—typically involve clinical monitoring in health-care settings, along with vaccination campaigns. But scientists have started looking to wastewater, too.

Along with various bodily fluids, we all shed viruses and bacteria into wastewater, whether that’s through brushing our teeth, showering, or using the toilet. The idea of looking for these pathogens in wastewater to track diseases has been around for a while, but things really kicked into gear during the covid-19 pandemic, when scientists found that the coronavirus responsible for the disease was shed in feces.

This led Marlene Wolfe of Emory University and Alexandria Boehm of Stanford University to establish WastewaterSCAN, an academic-led program developed to analyze wastewater samples across the US. Covid was just the beginning, says Wolfe. “Over the years we have worked to expand what can be monitored,” she says.

Two years ago, for a previous edition of the Checkup, Wolfe told Cassandra Willyard that wastewater surveillance of measles was “absolutely possible,” as the virus is shed in urine. The hope was that this approach could shed light on measles outbreaks in a community, even if members of that community weren’t able to access health care and receive an official diagnosis. And that it could highlight when and where public health officials needed to act to prevent measles from spreading. Evidence that it worked as an effective public health measure was, at the time, scant.

Since then, she and her colleagues have developed a test to identify measles RNA. They trialed it at two wastewater treatment plants in Texas between December 2024 and May 2025. At each site, the team collected samples two or three times a week and tested them for measles RNA.

Over that period, the team found measles RNA in 10.5% of the samples they collected, as reported in a preprint paper published at medRxiv in July and currently under review at a peer-reviewed journal. The first detection came a week before the first case of measles was officially confirmed in the area. That’s promising—it suggests that wastewater surveillance might pick up measles cases early, giving public health officials a head start in efforts to limit any outbreaks.

There are more promising results from a team in Canada. Mike McKay and Ryland Corchis-Scott at the University of Windsor in Ontario and their colleagues have also been testing wastewater samples for measles RNA. Between February and November 2025, the team collected samples from a wastewater treatment facility serving over 30,000 people in Leamington, Ontario. 

These wastewater tests are somewhat limited—even if they do pick up measles, they won’t tell you who has measles, where exactly infections are occurring, or even how many people are infected. McKay and his colleagues have begun to make some progress here. In addition to monitoring the large wastewater plant, the team used tampons to soak up wastewater from a hospital lateral sewer.

They then compared their measles test results with the number of clinical cases in that hospital. This gave them some idea of the virus’s “shedding rate.” When they applied this to the data collected from the Leamington wastewater treatment facility, the team got estimates of measles cases that were much higher than the figures officially reported. 

Their findings track with the opinions of local health officials (who estimate that the true number of cases during the outbreak was around five to 10 times higher than the confirmed case count), the team members wrote in a paper published on medRxiv a couple of weeks ago.

There will always be limits to wastewater surveillance. “We’re looking at the pool of waste of an entire community, so it’s very hard to pull in information about individual infections,” says Corchis-Scott.

Wolfe also acknowledges that “we have a lot to learn about how we can best use the tools so they are useful.” But her team at WastewaterSCAN has been testing wastewater across the US for measles since May last year. And their findings are published online and shared with public health officials.

In some cases, the findings are already helping inform the response to measles. “We’ve seen public health departments act on this data,” says Wolfe. Some have issued alerts, or increased vaccination efforts in those areas, for example. “[We’re at] a point now where we really see public health departments, clinicians, [and] families using that information to help keep themselves and their communities safe,” she says.

McKay says his team has stopped testing for measles because the Ontario outbreak “has been declared over.” He says testing would restart if and when a single new case of measles is confirmed in the region, but he also thinks that his research makes a strong case for maintaining a wastewater surveillance system for measles.

McKay wonders if this approach might help Canada regain its measles elimination status. “It’s sort of like [we’re] a pariah now,” he says. If his approach can help limit measles outbreaks, it could be “a nice tool for public health in Canada to [show] we’ve got our act together.”

This article first appeared in The Checkup, MIT Technology Review’s weekly biotech newsletter. To receive it in your inbox every Thursday, and read articles like this first, sign up here.

Earlier this week, MIT Technology Review published its annual list of Ten Breakthrough Technologies. As always, it features technologies that made the news last year, and which—for better or worse—stand to make waves in the coming years. They’re the technologies you should really be paying attention to.

This year’s list includes tech that’s set to transform the energy industry, artificial intelligence, space travel—and of course biotech and health. Our breakthrough biotechnologies for 2026 involve editing a baby’s genes and, separately, resurrecting genes from ancient species. We also included a controversial technology that offers parents the chance to screen their embryos for characteristics like height and intelligence. Here’s the story behind our biotech choices.

A base-edited baby!

In August 2024, KJ Muldoon was born with a rare genetic disorder that allowed toxic ammonia to build up in his blood. The disease can be fatal, and KJ was at risk of developing neurological disorders. At the time, his best bet for survival involved waiting for a liver transplant.

Then he was offered an experimental gene therapy—a personalized “base editing” treatment designed to correct the specific genetic “misspellings” responsible for his disease. It seems to have worked! Three doses later, KJ is doing well. He took his first steps in December, shortly before spending his first Christmas at home.

KJ’s story is hugely encouraging. The team behind his treatment is planning a clinical trial for infants with similar disorders caused by different genetic mutations. The team members hope to win regulatory approval on the back of a small trial—a move that could make the expensive treatment (KJ’s cost around $1 million) more accessible, potentially within a few years.

Others are getting in on the action, too. Fyodor Urnov, a gene-editing scientist at the University of California, Berkeley, assisted the team that developed KJ’s treatment. He recently cofounded Aurora Therapeutics, a startup that hopes to develop gene-editing drugs for another disorder called phenylketonuria (PKU). The goal is to obtain regulatory approval for a single drug that can then be adjusted or personalized for individuals without having to go through more clinical trials.

US regulators seem to be amenable to the idea and have described a potential approval pathway for such “bespoke, personalized therapies.” Watch this space.

Gene resurrection

It was a big year for Colossal Biosciences, the biotech company hoping to “de-extinct” animals like the woolly mammoth and the dodo. In March, the company created what it called “woolly mice”—rodents with furry coats and curly whiskers akin to those of woolly mammoths.

The company made an even more dramatic claim the following month, when it announced it had created three dire wolves. These striking snow-white animals were created by making 20 genetic changes to the DNA of gray wolves based on genetic research on ancient dire wolf bones, the company said at the time.

Whether these animals can really be called dire wolves is debatable, to say the least. But the technology behind their creation is undeniably fascinating. We’re talking about the extraction and analysis of ancient DNA, which can then be introduced into cells from other, modern-day species.

Analysis of ancient DNA can reveal all sorts of fascinating insights into human ancestors and other animals. And cloning, another genetic tool used here, has applications not only in attempts to re-create dead pets but also in wildlife conservation efforts. Read more here.

Embryo scoring

IVF involves creating embryos in a lab and, typically, “scoring” them on their likelihood of successful growth before they are transferred to a person’s uterus. So far, so uncontroversial.

Recently, embryo scoring has evolved. Labs can pinch off a couple of cells from an embryo, look at its DNA, and screen for some genetic diseases. That list of diseases is increasing. And now some companies are taking things even further, offering prospective parents the opportunity to select embryos for features like height, eye color, and even IQ.

This is controversial for lots of reasons. For a start, there are many, many factors that contribute to complex traits like IQ (a score that doesn’t capture all aspects of intelligence at any rate). We don’t have a perfect understanding of those factors, or how selecting for one trait might influence another.

Some critics warn of eugenics. And others note that whichever embryo you end up choosing, you can’t control exactly how your baby will turn out (and why should you?!). Still, that hasn’t stopped Nucleus, one of the companies offering these services, from inviting potential customers to have their “best baby.” Read more here.

This article first appeared in The Checkup, MIT Technology Review’s weekly biotech newsletter. To receive it in your inbox every Thursday, and read articles like this first, sign up here.

Kyle “KJ” Muldoon Jr. was born with a rare genetic disorder that left his body unable to remove toxic ammonia from his blood. He was lethargic and at risk of developing neurological disorders. The condition can be fatal. 

KJ joined a waiting list for a liver transplant. Then Rebecca Ahrens-Nicklas and Kiran Musunuru at the University of Pennsylvania offered his parents an alternative. The pair were developing potential gene-editing therapies for diseases like KJ’s. His parents signed him up.

The team set to work developing a tailored treatment using base editing—a form of CRISPR that can correct genetic “misspellings” by changing single bases, the basic units of DNA. They tested it in human cells, mice, and monkeys, and KJ received an initial low dose when he was seven months old. He later received two higher doses. Today, KJ is doing well. At an event in October, his happy parents described how he was meeting all his developmental milestones.

Others have received gene-editing therapies intended to treat conditions including sickle cell disease and a predisposition to high cholesterol. But KJ was the first to receive a personalized treatment—one that was designed just for him and will probably never be used again. 

The expense was similar to that of a liver transplant, which costs around $1 million, says Musunuru, but he thinks that will come down to a few hundred thousand dollars per treatment within the next few years.

KJ’s doctors will monitor him for years, and they can’t yet say how effective this gene-editing approach is. But they plan to launch a clinical trial to test such personalized treatments in children with similar disorders caused by “misspelled” genes that can be targeted with base editing.

They’re hopeful that approval by the US Food and Drug Administration will soon follow. Musunuru says the FDA has agreed on a trial protocol that could involve as few as five patients with at least three genetic variants. In November, FDA administrators described in the New England Journal of Medicine how the agency might approve personalized therapies like KJ’s using a new pathway.

Here at MIT Technology Review we’ve been writing about the gene-editing technology CRISPR since 2013, calling it the biggest biotech breakthrough of the century. Yet so far, there’s been only one gene-editing drug approved. It’s been used commercially on only about 40 patients, all with sickle-cell disease.

It’s becoming clear that the impact of CRISPR isn’t as big as we all hoped. In fact, there’s a pall of discouragement over the entire field—with some journalists saying the gene-editing revolution has “lost its mojo.”

So what will it take for CRISPR to help more people? A new startup says the answer could be an “umbrella approach” to testing and commercializing treatments. Aurora Therapeutics, which has $16 million from Menlo Ventures and counts CRISPR co-inventor Jennifer Doudna as an advisor, essentially hopes to win approval for gene-editing drugs that can be slightly adjusted, or personalized, without requiring costly new trials or approvals for every new version.

The need to change regulations around gene-editing treatments was endorsed in November by the head of the US Food and Drug Administration, Martin Makary, who said the agency would open a “new” regulatory pathway for “bespoke, personalized therapies” that can’t easily be tested in conventional ways. 

Aurora’s first target, the rare inherited disease phenylketonuria, also known as PKU, is a case in point. People with PKU lack a working version of an enzyme needed to use up the amino acid phenylalanine, a component of pretty much all meat and protein. If the amino acid builds up, it causes brain damage. So patients usually go on an onerous “diet for life” of special formula drinks and vegetables.

In theory, gene editing can fix PKU. In mice, scientists have already restored the gene for the enzyme by rewriting DNA in liver cells, which both make the enzyme and are some of the easiest to reach with a gene-editing drug. The problem is that in human patients, many different mutations can affect the critical gene. According to Cory Harding, a researcher at Oregon Health Sciences University, scientists know about 1,600 different DNA mutations that cause PKU.

There’s no way anyone will develop 1,600 different gene-editing drugs. Instead, Aurora’s goal is to eventually win approval for a single gene editor that, with minor adjustments, could be used to correct several of the most common mutations, including one that’s responsible for about 10% of the estimated 20,000 PKU cases in the US.

“We can’t have a separate clinical trial for each mutation,” says Edward Kaye, the CEO of Aurora. “The way the FDA approves gene editing has to change, and I think they’ve been very understanding that is the case.”

A gene editor is a special protein that can zero in on a specific location in the genome and change it. To prepare one, Aurora will put genetic code for the editor into a nanoparticle along with a targeting molecule. In total, it will involve about 5,000 gene letters. But only 20 of them need to change in order to redirect the treatment to repair a different mutation.

“Over 99% of the drug stays the same,” says Johnny Hu, a partner at Menlo Ventures, which put up the funding for the startup.

The new company came together after Hu met over pizza with Fyodor Urnov, an outspoken gene-editing scientist at the University of California, Berkeley, who is Aurora’s cofounder and sits on its board.

In 2022, Urnov had written a New York Times editorial bemoaning the “chasm” between what editing technology can do and the “legal, financial, and organizational” realities preventing researchers from curing people.

“I went to Fyodor and said, ‘Hey, we’re getting all these great results in the clinic with CRISPR, but why hasn’t it scaled?” says Hu. Part of the reason is that most gene-editing companies are chasing the same few conditions, such as sickle-cell, where (as luck would have it) a single edit works for all patients. But that leaves around 400 million people who have 7,000 other inherited conditions without much hope to get their DNA fixed, Urnov estimated in his editorial.

Then, last May, came the dramatic demonstration of the first fully “personalized” gene-editing treatment. A team in Philadelphia, assisted by Urnov and others, succeeded in correcting the DNA of a baby, named KJ Muldoon, who had an entirely unique mutation that caused a metabolic disease. Though it didn’t target PKU, the project showed that gene editing could theoretically fix some inherited diseases “on demand.” 

It also underscored a big problem. Treating a single child required a large team and cost millions in time, effort, and materials—all to create a drug that would never be used again. 

That’s exactly the sort of situation the new “umbrella” trials are supposed to address. Kiran Musunuru, who co-led the team at the University of Pennsylvania, says he’s been in discussions with the FDA to open a study of bespoke gene editors this year focusing on diseases of the type Baby KJ had, called urea cycle disorders. Each time a new patient appears, he says, they’ll try to quickly put together a variant of their gene-editing drug that’s tuned to fix that child’s particular genetic problem.

Musunuru, who isn’t involved with Aurora, does not think the company’s plans for PKU count as fully personalized editors. “These corporate PKU efforts have nothing whatsoever to do with Baby KJ,” he says. He says his center continues to focus on mutations “so ultra-rare that we don’t see any scenario where a for-profit gene-editing company would find that indication to be commercially viable.”

Instead, what’s occurring in PKU, says Musunuru, is that researchers have realized they can assemble “a bunch” of the most frequent mutations “into a large enough group of patients to make a platform PKU therapy commercially viable.” 

While that would still leave out many patients with extra-rare gene errors, Musunuru says any gene-editing treatment at all would still be “a big improvement over the status quo, which  is zero genetic therapies for PKU.”

The new year has barely begun, but the first days of 2026 have brought big news for health. On Monday, the US’s federal health agency upended its recommendations for routine childhood vaccinations—a move that health associations worry puts children at unnecessary risk of preventable disease.

There was more news from the federal government on Wednesday, when health secretary Robert F. Kennedy Jr. and his colleagues at the Departments of Health and Human Services and Agriculture unveiled new dietary guidelines for Americans. And they are causing a bit of a stir.

That’s partly because they recommend products like red meat, butter, and beef tallow—foods that have been linked to cardiovascular disease, and that nutrition experts have been recommending people limit in their diets.

These guidelines are a big deal—they influence food assistance programs and school lunches, for example. So this week let’s look at the good, the bad, and the ugly advice being dished up to Americans by their government.

The government dietary guidelines have been around since the 1980s. They are updated every five years, in a process that typically involves a team of nutrition scientists who have combed over scientific research for years. That team will first publish its findings in a scientific report, and, around a year later, the finalized Dietary Guidelines for Americans are published.

The last guidelines covered the period 2020 to 2025, and new guidelines were expected in the summer of 2025. Work had already been underway for years; the scientific report intended to inform them was published back in 2024. But the publication of the guidelines was delayed by last year’s government shutdown, Kennedy said last year. They were finally published yesterday.

Nutrition experts had been waiting with bated breath. Nutrition science has evolved slightly over the last five years, and some were expecting to see new recommendations. Research now suggests, for example, that there is no “safe” level of alcohol consumption.

We are also beginning to learn more about health risks associated with some ultraprocessed foods (although we still don’t have a good understanding of what they might be, or what even counts as “ultraprocessed”.) And some scientists were expecting to see the new guidelines factor in environmental sustainability, says Gabby Headrick, the associate director of food and nutrition policy at George Washington University’s Institute for Food Safety & Nutrition Security in Washington DC.

They didn’t.

Many of the recommendations are sensible. The guidelines recommend a diet rich in whole foods, particularly fresh fruits and vegetables. They recommend avoiding highly processed foods and added sugars. They also highlight the importance of dietary protein, whole grains, and “healthy” fats.

But not all of them are, says Headrick. The guidelines open with a “new pyramid” of foods. This inverted triangle is topped with “protein, dairy, and healthy fats” on one side and “vegetables and fruits” on the other.

There are a few problems with this image. For starters, its shape—nutrition scientists have long moved on from the food pyramids of the 1990s, says Headrick. They’re confusing and make it difficult for people to understand what the contents of their plate should look like. That’s why scientists now use an image of a plate to depict a healthy diet.

“We’ve been using MyPlate to describe the dietary guidelines in a very consumer-friendly, nutrition-education-friendly way for over the last decade now,” says Headrick. (The UK’s National Health Service takes a similar approach.)

And then there’s the content of that food pyramid. It puts a significant focus on meat and whole-fat dairy produce. The top left image—the one most viewers will probably see first—is of a steak. Smack in the middle of the pyramid is a stick of butter. That’s new. And it’s not a good thing.

While both red meat and whole-fat dairy can certainly form part of a healthy diet, nutrition scientists have long been recommending that most people try to limit their consumption of these foods. Both can be high in saturated fat, which can increase the risk of cardiovascular disease—the leading cause of death in the US. In 2015, on the basis of limited evidence, the World Health Organization classified red meat as “probably carcinogenic to humans.” 

Also concerning is the document’s definition of “healthy fats,” which includes butter and beef tallow (a MAHA favorite). Neither food is generally considered to be as healthy as olive oil, for example. While olive oil contains around two grams of saturated fat per tablespoon, a tablespoon of beef tallow has around six grams of saturated fat, and the same amount of butter contains around seven grams of saturated fat, says Headrick.

“I think these are pretty harmful dietary recommendations to be making when we have established that those specific foods likely do not have health-promoting benefits,” she adds.

Red meat is not exactly a sustainable food, and neither are dairy products. And the advice on alcohol is relatively vague, recommending that people “consume less alcohol for better overall health” (which might leave you wondering: Less than what?).

There are other questionable recommendations in the guidelines. Americans are advised to include more protein in their diets—at levels between 1.2 and 1.6 grams daily per kilo of body weight, 50% to 100% more than recommended in previous guidelines. There’s a risk that increasing protein consumption to such levels could raise a person’s intake of both calories and saturated fats to unhealthy levels, says José Ordovás, a senior nutrition scientist at Tufts University. “I would err on the low side,” he says.

Some nutrition scientists are questioning why these changes have been made. It’s not as though the new recommendations were in the 2024 scientific report. And the evidence on red meat and saturated fat hasn’t changed, says Headrick.

In reporting this piece, I contacted many contributors to the previous guidelines, and some who had led research for 2024’s scientific report. None of them agreed to comment on the new guidelines on the record. Some seemed disgruntled. One merely told me that the process by which the new guidelines had been created was “opaque.”

“These people invested a lot of their time, and they did a thorough job [over] a couple of years, identifying [relevant scientific studies],” says Ordovás. “I’m not surprised that when they see that [their] work was ignored and replaced with something [put together] quickly, that they feel a little bit disappointed,” he says.

This article first appeared in The Checkup, MIT Technology Review’s weekly biotech newsletter. To receive it in your inbox every Thursday, and read articles like this first, sign up here.

The Italian neurosurgeon Sergio Canavero has been preparing for a surgery that might never happen. His idea? Swap a sick person’s head—or perhaps just the brain—onto a younger, healthier body.

Canavero caused a stir in 2017 when he announced that a team he advised in China had exchanged heads between two corpses. But he never convinced skeptics that his technique could succeed—or to believe his claim that a procedure on a live person was imminent. The Chicago Tribune labeled him the “P.T. Barnum of transplantation.”

Canavero withdrew from the spotlight. But the idea of head transplants isn’t going away. Instead, he says, the concept has recently been getting a fresh look from life-extension enthusiasts and stealth Silicon Valley startups.

Career path

It’s been rocky. After he began publishing his surgical ideas a decade ago, Canavero says, he got his “pink slip” from the Molinette Hospital in Turin, where he’d spent 22 years on staff. “I’m an out-of-the-establishment guy. So that has made things harder, I have to say,” he says.  

Why he persists

No other solution to aging is on the horizon. “It’s become absolutely clear over the past years that the idea of some incredible tech to rejuvenate elderly people—­happening in some secret lab, like Google—is really going nowhere,” he says. “You have to go for the whole shebang.”

The whole shebang?

He means getting a new body, not just one new organ. Canavero has an easy mastery of English idioms and an unexpected Southern twang. He says that’s due to a fascination with American comics as a child. “For me, learning the language of my heroes was paramount,” he says. “So I can shoot the breeze.” 

Cloned bodies

Canavero is now an independent investigator and has advised entrepreneurs who want to create brainless human clones as a source of DNA-matched organs that wouldn’t get rejected by a recipient’s immune system. “I can tell you there are guys from top universities involved,” he says.

What’s next

Combining the necessary technologies, like reliably precise surgical robots and artificial wombs to grow the clones, is going to be complex and very, very expensive. Canavero lacks the funds to take his plans further, but he believes “the money is out there” for a commercial moonshot project: “What I say to the billionaires is ‘Come together.’ You will all have your own share, plus make yourselves immortal.”

At first glance, it looks like the start of a human pregnancy: A ball-shaped embryo presses gently into the receptive lining of the uterus and then grips tight, burrowing in as the first tendrils of a future placenta appear. 

This is implantation—the moment that pregnancy officially begins.

Only none of it is happening inside a body. These images were captured in a Beijing laboratory, inside a microfluidic chip, as scientists watched the scene unfold.

In three papers published this week by Cell Press, scientists are reporting what they call the most accurate efforts yet to mimic the first moments of pregnancy in the lab. They’ve taken human embryos from IVF centers and let these merge with “organoids” made of endometrial cells, which form the lining of the uterus.

The reports—two from China and a third involving a collaboration among researchers in the United Kingdom, Spain, and the US—show how scientists are using engineered tissues to better understand early pregnancy and potentially improve IVF outcomes.

“You have an embryo and the endometrial organoid together,” says Jun Wu, a biologist at the University of Texas Southwestern Medical Center, in Dallas, who contributed to both Chinese reports. “That’s the overarching message of all three papers.”

According to the papers, these 3D combinations are the most complete re-creations yet of the first days of pregnancy and should be useful for studying why IVF treatments often fail.

In each case, the experiments were stopped when the embryos were two weeks old, if not sooner. That is due to legal and ethical rules that typically restrict scientists from going any further than 14 days.

In your basic IVF procedure, an egg is fertilized in the lab and allowed to develop into a spherical embryo called a blastocyst—a process that takes a few days. That blastocyst then gets put into a patient’s uterus in the hope it will establish itself there and ultimately become a baby.

But that’s a common failure point. Many patients will learn that their IVF procedure didn’t work because an embryo never attached.

In the new reports, it’s that initial bond between mother and embryo that is being reproduced in the lab. “IVF means in vitro fertilization, but now this is the stage of in vitro implantation,” says Matteo Molè, a biologist at Stanford University whose results with collaborators in Europe are among those published today. “Considering that implantation is a barrier [to pregnancy], we have the potential to increase the success rate if we can model it in the laboratory.”

Normally implantation is entirely hidden from view because it occurs in someone’s uterus, says Hongmei Wang, a developmental biologist at the Beijing Institute for Stem Cell and Regenerative Medicine, who co-led the effort there. Wang often studies monkeys because she can interrupt their pregnancies to collect the tissues she needs to see. “We’ve always hoped to understand human embryo implantation, but we have lacked a way to do so,” she says. “It’s all happening in the uterus.”

In the Beijing study, researchers tested about 50 donated IVF embryos, but they also ran a thousand more experiments using so-called blastoids. The latter are mimics of early-stage human embryos manufactured from stem cells. Blastoids are easy to make in large numbers and, since they aren’t true embryos, don’t have as many ethical rules on their use.

“The question was, if we have these blastoids, what can we use them for?” says Leqian Yu, the senior author of the report from the Beijing Institute. “The obvious next step was implantation. So how do you do that?”

For the Beijing team, the answer was to build a soft silicone chamber with tiny channels to add nutrients and a space to grow the uterine organoid. After that, blastoids—or real embryos—could be introduced through a window in the device, so the “pregnancy” could start.

“The key question we want to try to answer is what is the first cross-talk between embryo and mother,” says Yu. “I think this is maybe the first time we can see the entire process.”

Medical applications

This isn’t the first time researchers have tried using organoids for this kind of research. At least two startup companies have raised funds to commercialize similar systems—in some cases presenting the organoids as a tool to predict IVF success. In addition to Dawn Bio, a startup based in Vienna, there is Simbryo Technologies, in Houston, which last month said it would begin offering “personalized” predictions for IVF patients using blastoids and endometrial organoids.

To do that test, doctors will take a biopsy of a patient’s uterine lining and grow organoids from it. After that, blastoids will be added to the organoids to gauge whether a woman is likely to be able to support a pregnancy or not. If the blastoids don’t start to implant, it could mean the patient’s uterus isn’t receptive and is the reason IVF isn’t working.

The Beijing team thinks the pregnancy organoids could also be used to identify drugs that might help those patients. In their paper, they describe how they made organoids out of tissue taken from women who’ve had repeated IVF failures. Then they tested 1,119 approved drugs on those samples to see if anything improved.

Several seemed to have helpful effects. One chemical, avobenzone, an ingredient in some types of sunblock, increased the chance that a blastoid would start implanting from just 5% of the time to around 25% of the time. Yu says his center hopes to eventually start a clinical trial if they can find the right drug to try. 

Artificial womb?

The Beijing group is working on ways to improve the organoid system so that it’s even more realistic. Right now, it lacks important cell types, including immune cells and a blood supply. Yu says a next step he’s working on is to add blood vessels and tiny pumps to his chip device, so that he can give the organoids a kind of rudimentary circulation.

This means that in the near future, blastoids or embryos could likely be grown longer, raising questions about how far scientists will be able to take pregnancy in the lab. “I think this technology does raise the possibility of growing things longer,” says Wu, who says some view the research as an initial step toward creating babies entirely outside the body.

However, Wu says incubating a human to term in the laboratory remains impossible, for the time being. “This technology is certainly related to ectogenesis, or development outside the body,” he says. “But I don’t think it’s anywhere near an artificial womb. That’s still science fiction.”

At some point next month, a handful of volunteers will be injected with two experimental gene therapies as part of an unusual clinical trial. The drugs are potential longevity therapies, says Ivan Morgunov, the CEO of Unlimited Bio, the company behind the trial. His long-term goal: to achieve radical human life extension.

The 12 to 15 volunteers—who will be covering their own travel and treatment costs—will receive a series of injections in the muscles of their arms and legs. One of the therapies is designed to increase the blood supply to those muscles. The other is designed to support muscle growth. The company hopes to see improvements in strength, endurance, and recovery. It also plans to eventually trial similar therapies in the scalp (for baldness) and penis (for erectile dysfunction).

But some experts are concerned that the trial involves giving multiple gene therapies to small numbers of healthy people. It will be impossible to draw firm conclusions from such a small study, and the trial certainly won’t reveal anything about longevity, says Holly Fernandez Lynch, a lawyer and medical ethicist at the University of Pennsylvania in Philadelphia.

Unlimited Bio’s blood supply therapy is already accessible at clinics in Honduras and Mexico, says Morgunov—and the company is already getting some publicity. Khloe Kardashian tagged Unlimited Bio in a Facebook post about stem-cell treatments she and her sister Kim had received at the Eterna clinic in Mexico in August. And earlier this week, the biohacking influencer Dave Asprey posted an Instagram Reel of himself receiving one of the treatments in Mexico; it was shared with 1.3 million Instagram followers. In the video, Eterna’s CEO, Adeel Khan, says that the therapy can “help with vascular health systemically.” “I’m just upgrading my system for a little while to reduce my age and reduce my vascular risk,” Asprey said.

Genes for life

Gene therapies typically work by introducing new genetic code into the body’s cells. This code is then able to make proteins. Existing approved gene therapies have typically been developed for severe diseases in which the target proteins are either missing or mutated.

But several groups are exploring gene therapies for healthy people. One of these companies is Minicircle, which developed a gene therapy to increase production of follistatin, a protein found throughout the body that has many roles and is involved in muscle growth. The company says this treatment will increase muscle mass—and help people live longer. Minicircle is based in Próspera, a special economic zone in Honduras with its own bespoke regulatory system. Anyone can visit the local clinic and receive that therapy, for a reported price of $25,000. And many have, including the wealthy longevity influencer Bryan Johnson, who promoted the therapy in a Netflix documentary.

Unlimited Bio’s Morgunov, a Russian-Israeli computer scientist, was inspired by Minicircle’s story. He is also interested in longevity. Specifically, he’s committed to radical life extension and has said that he could be part of “the last generation throughout human history to die from old age.” He believes the biggest “bottleneck” slowing progress toward anti-aging or lifespan-extending therapies is drug regulation. So he, too, incorporated his own biotech company in Próspera.

“A company like ours couldn’t exist outside of Próspera,” says Unlimited Bio’s chief operating officer, Vladimir Leshko.

There, Morgunov and his colleagues are exploring two gene therapies. One of these is another follistatin therapy, which the team hopes will increase muscle mass. The other codes for a protein called vascular endothelial growth factor, or VEGF. This compound is known to encourage the growth of blood vessels. Morgunov and his colleagues hope the result will be increased muscle growth, enhanced muscle repair, and longer life. Neither treatment is designed to alter a recipient’s DNA, and therefore it won’t be inherited by future generations.

The combination of the two therapies could benefit healthy people and potentially help them live longer, says Leshko, a former electrical engineer and professional poker player who retrained in biomedical engineering. “We would say that it’s a preventive-slash-enhancing indication,” he says. “Potentially participants can experience faster recovery from exercise, more strength, and more endurance.”

Of the 12 to 15 volunteers who participate in the trial, half will receive only the follistatin therapy. The other half will receive both the VEGF and the follistatin therapies. The treatments will involve a series of injections throughout large muscles in the arms and legs, says Morgunov.

He is confident that the VEGF therapy is safe. It was approved in Russia over a decade ago to treat lower-limb ischemia—a condition that can cause pain, numbness, and painful ulcers in the legs and feet. Morgunov reckons, based on previously published estimates, that around 10,000 people in Russia have already had the drug, although he says he hasn’t “done deep fact-checking on that.”

Other researchers aren’t convinced.

Limited bio

VEGF is a powerful compound, says Seppo Ylä-Herttuala, a professor of molecular medicine at the University of Eastern Finland who has been studying VEGF and potential VEGF therapies for decades. He doesn’t know how many people have had VEGF gene therapy in Russia. But he does know that the safety of the therapy will depend on how much is administered and where. Previous attempts to inject the therapy into the heart, for example, have resulted in edema, a sometimes fatal buildup of fluid. Even if the therapy is injected elsewhere, VEGF can travel around the body, he says. If it gets to the eye, for example, it could cause blindness. Leshko counters that the VEGF should remain where it is injected, and any other circulation in the body, if it occurs, should be short-lived. 

And while the therapy has been approved in Russia, there’s a reason it hasn’t been approved elsewhere, says Ylä-Herttuala: The clinical trials were not as rigorous as they could have been. While “it probably works in some patients,” he says, the evidence to support the use of this therapy is weak. At any rate, he adds, VEGF will only support the growth of blood vessels—it won’t tackle aging.  “VEGF is not a longevity drug,” he says.

Leshko points to a 2021 study in mice, which suggested that a lack of VEGF activity might drive aging in the rodents. “We’re convinced it qualifies as a potential longevity drug,” he says.

There is even less data about follistatin. Minicircle, the company selling another follistatin gene therapy, has not published any rigorous clinical trial data. So far, much of the evidence for follistatin’s effects comes from research in rodents, says Ylä-Herttuala.

Clinical trials like this one should gather more information, both about the therapies and about the methods used to get those therapies into the body. Unlimited Bio’s VEGF therapy will be delivered via a circular piece of genetic code called a plasmid. Its follistatin therapy, on the other hand, will be delivered via an adeno-associated virus (AAV). Plasmid therapies are easier to make, and they have a shorter lifespan in the body—only a matter of days. They are generally considered to be safer than AAV therapies. AAV therapies, on the other hand, tend to stick around for months, says Ylä-Herttuala. And they can trigger potentially dangerous immune reactions.

It’s debatable whether healthy people should be exposed to these risks, says Fernandez Lynch. The technology “still has serious questions about its safety and effectiveness,” even for people with life-threatening diseases, she says. “If you are a healthy person, the risk of harm is more substantial because it’ll be more impactful on your life.”

But Leshko is adamant. “Over 120,000 humans die DAILY from age-related causes,” he wrote in an email. “Building ‘ethical’ barriers around ‘healthy’ human (in fact, aging human) trials is unethical.” Morgunov did not respond to a request for comment.

Some people want to take those risks anyway. In his video, the biohacker influencer Asprey—who has publicly stated that he’s “going to live to 180”—described VEGF as a “longevity compound,” and Eterna’s CEO Khan, who delivered the treatment, described it as “the ultimate upgrade.” Neither Asprey nor Khan clinic responded to requests for comment. 

Michael Gusmano, a professor of health policy at Lehigh University in Bethlehem, Pennsylvania, worries that this messaging might give trial participants unrealistic expectations about how they might benefit. There is “huge potential for therapeutic misconception when you have some kind of celebrity online influencer touting something about which there is relatively sparse scientific evidence,” he says. In reality, he adds, “the only thing you can guarantee is that [the volunteers] will be contributing to our knowledge of how this intervention works.”

“I would certainly not recommend that anyone I know enter into such a trial,” says Gusmano.

A penis project

The muscle study is only the first step. The Unlimited Bio team hopes to trial the VEGF therapy for baldness and erectile dysfunction, too. Leshko points to research in mice that links high VEGF levels to larger, denser hair follicles. He hopes to test a series of VEGF therapy injections into the scalps of volunteers. Morgunov, who is largely bald, has already started to self-experiment with the approach.

An erectile dysfunction trial may follow. “That one we think has great potential because injecting gene therapy into the penis sounds exciting,” says Leshko. A protocol for that trial has not yet been finalized, but he imagines it would involve “five to 10” injections.

Ylä-Herttuala isn’t optimistic about either approach. Hair growth is largely hormonal, he says. And injecting anything into a penis risks damaging it (although Leshko points out that a similar approach was taken by another company almost 20 years ago). Injecting a VEGF gene therapy into the penis would also risk edema there, Ylä-Herttuala adds.

And he points out that we already have some treatments for hair loss and erectile dysfunction. While they aren’t perfect, their existence does raise the bar for any potential future therapies—not only do they have to be safe and effective, but they must be safer or more effective than existing ones.

That doesn’t mean the trials will flop. No small trial can be definitive, but it could still provide some insight into how these drugs are working. It is possible that the therapies will increase muscle mass, at least, and that this could be beneficial to the healthy recipients, says Ylä-Herttuala. 

Before our call, he had taken a look at Unlimited Bio’s website, which carries the tagline “The Most Advanced Rejuvenation Solution.” “They promise a lot,” he said. “I hope it’s true.”

Correction: This story was corrected to note that half of trial volunteers volunteers receive only the follistatin therapy.

In just a couple of weeks, we’ll be bidding farewell to 2025. And what a year it has been! Artificial intelligence is being incorporated into more aspects of our lives, weight-loss drugs have expanded in scope, and there have been some real “omg” biotech stories from the fields of gene therapy, IVF, neurotech, and more.   

As always, the team at MIT Technology Review has been putting together our 2026 list of breakthrough technologies. That will be published in the new year (watch this space). In the meantime, my colleague Antonio Regalado has compiled his traditional list of the year’s worst technologies.

I’m inviting you to put your own memory to the test. Just how closely have you been paying attention to the Checkup emails that have been landing in your inbox this year?!

This article first appeared in The Checkup, MIT Technology Review’s weekly biotech newsletter. To receive it in your inbox every Thursday, and read articles like this first, sign up here.

This week I’ve been thinking about babies. Healthy ones. Perfect ones. As you may have read last week, my colleague Antonio Regalado came face to face with a marketing campaign in the New York subway asking people to “have your best baby.”

The company behind that campaign, Nucleus Genomics, says it offers customers a way to select embryos for a range of traits, including height and IQ. It’s an extreme proposition, but it does seem to be growing in popularity—potentially even in the UK, where it’s illegal.

The other end of the screening spectrum is transforming too. Carrier screening, which tests would-be parents for hidden genetic mutations that might affect their children, initially involved testing for specific genes in at-risk populations.

Now, it’s open to almost everyone who can afford it. Companies will offer to test for hundreds of genes to help people make informed decisions when they try to become parents. But expanded carrier screening comes with downsides. And it isn’t for everyone.

That’s what I found earlier this week when I attended the Progress Educational Trust’s annual conference in London.

First, a bit of background. Our cells carry 23 pairs of chromosomes, each with thousands of genes. The same gene—say, one that codes for eye color—can come in different forms, or alleles. If the allele is dominant, you only need one copy to express that trait. That’s the case for the allele responsible for brown eyes. 

If the allele is recessive, the trait doesn’t show up unless you have two copies. This is the case with the allele responsible for blue eyes, for example.

Things get more serious when we consider genes that can affect a person’s risk of disease. Having a single recessive disease-causing gene typically won’t cause you any problems. But a genetic disease could show up in children who inherit the same recessive gene from both parents. There’s a 25% chance that two “carriers” will have an affected child. And those cases can come as a shock to the parents, who tend to have no symptoms and no family history of disease.

This can be especially problematic in communities with high rates of those alleles. Consider Tay-Sachs disease—a rare and fatal neurodegenerative disorder caused by a recessive genetic mutation. Around one in 25 members of the Ashkenazi Jewish population is a healthy carrier for Tay-Sachs. Screening would-be parents for those recessive genes can be helpful. Carrier screening efforts in the Jewish community, which have been running since the 1970s, have massively reduced cases of Tay-Sachs.

Expanded carrier screening takes things further. Instead of screening for certain high-risk alleles in at-risk populations, there’s an option to test for a wide array of diseases in prospective parents and egg and sperm donors. The companies offering these screens “started out with 100 genes, and now some of them go up to 2,000,” Sara Levene, genetics counsellor at Guided Genetics, said at the meeting. “It’s becoming a bit of an arms race amongst labs, to be honest.”

There are benefits to expanded carrier screening. In most cases, the results are reassuring. And if something is flagged, prospective parents have options; they can often opt for additional testing to get more information about a particular pregnancy, for example, or choose to use other donor eggs or sperm to get pregnant. But there are also downsides. For a start, the tests can’t entirely rule out the risk of genetic disease.

Earlier this week, the BBC reported news of a sperm donor who had unwittingly passed on to at least 197 children in Europe a genetic mutation that dramatically increased the risk of cancer. Some of those children have already died.

It’s a tragic case. That donor had passed screening checks. The (dominant) mutation appears to have occurred in his testes, affecting around 20% of his sperm. It wouldn’t have shown up in a screen for recessive alleles, or even a blood test.

Even recessive diseases can be influenced by many genes, some of which won’t be included in the screen. And the screens don’t account for other factors that could influence a person’s risk of disease, such as epigenetics, microbiome, or even lifestyle.

“There’s always a 3% to 4% chance [of having] a child with a medical issue regardless of the screening performed,” said Jackson Kirkman-Brown, professor of reproductive biology at the University of Birmingham, at the meeting.

The tests can also cause stress. As soon as a clinician even mentions expanded carrier screening, it adds to the mental load of the patient, said Kirkman-Brown: “We’re saying this is another piece of information you need to worry about.”

People can also feel pressured to undergo expanded carrier screening even when they are ambivalent about it, said Heidi Mertes, a medical ethicist at Ghent University. “Once the technology is there, people feel like if they don’t take this opportunity up, then they are kind of doing something wrong or missing out,” she said.

My takeaway from the presentations was that while expanded carrier screening can be useful, especially for people from populations with known genetic risks, it won’t be for everyone.

I also worry that, as with the genetic tests offered by Nucleus, its availability gives the impression that it is possible to have a “perfect” baby—even if that only means “free from disease.” The truth is that there’s a lot about reproduction that we can’t control.

The decision to undergo expanded carrier screening is a personal choice. But as Mertes noted at the meeting: “Just because you can doesn’t mean you should.”

This article first appeared in The Checkup, MIT Technology Review’s weekly biotech newsletter. To receive it in your inbox every Thursday, and read articles like this first, sign up here.

One day this fall, I watched an electronic sign outside the Broadway-Lafayette subway station in Manhattan switch seamlessly between an ad for makeup and one promoting the website Pickyourbaby.com, which promises a way for potential parents to use genetic tests to influence their baby’s traits, including eye color, hair color, and IQ.

Inside the station, every surface was wrapped with more ads—babies on turnstiles, on staircases, on banners overhead. “Think about it. Makeup and then genetic optimization,” exulted Kian Sadeghi, the 26-year-old founder of Nucleus Genomics, the startup running the ads. To his mind, one should be as accessible as the other. 

Nucleus is a young, attention-seeking genetic software company that says it can analyze genetic tests on IVF embryos to score them for 2,000 traits and disease risks, letting parents pick some and reject others. This is possible because of how our DNA shapes us, sometimes powerfully. As one of the subway banners reminded the New York riders: “Height is 80% genetic.”

The day after the campaign launched, Sadeghi and I had briefly sparred online. He’d been on X showing off a phone app where parents can click through traits like eye color and hair color. I snapped back that all this sounded a lot like Uber Eats—another crappy, frictionless future invented by entrepreneurs, but this time you’d click for a baby.

I agreed to meet Sadeghi that night in the station under a banner that read, “IQ is 50% genetic.” He appeared in a puffer jacket and told me the campaign would soon spread to 1,000 train cars. Not long ago, this was a secretive technology to whisper about at Silicon Valley dinner parties. But now? “Look at the stairs. The entire subway is genetic optimization. We’re bringing it mainstream,” he said. “I mean, like, we are normalizing it, right?”

Normalizing what, exactly? The ability to choose embryos on the basis of predicted traits could lead to healthier people. But the traits mentioned in the subway—height and IQ—focus the public’s mind toward cosmetic choices and even naked discrimination. “I think people are going to read this and start realizing: Wow, it is now an option that I can pick. I can have a taller, smarter, healthier baby,” says Sadeghi.

Nucleus got its seed funding from Founders Fund, an investment firm known for its love of contrarian bets. And embryo scoring fits right in—it’s an unpopular concept, and professional groups say the genetic predictions aren’t reliable. So far, leading IVF clinics still refuse to offer these tests. Doctors worry, among other things, that they’ll create unrealistic parental expectations. What if little Johnny doesn’t do as well on the SAT as his embryo score predicted?

The ad blitz is a way to end-run such gatekeepers: If a clinic won’t agree to order the test, would-be parents can take their business elsewhere. Another embryo testing company, Orchid, notes that high consumer demand emboldened Uber’s early incursions into regulated taxi markets. “Doctors are essentially being shoved in the direction of using it, not because they want to, but because they will lose patients if they don’t,” Orchid founder Noor Siddiqui said during an online event this past August.

Sadeghi prefers to compare his startup to Airbnb. He hopes it can link customers to clinics, becoming a digital “funnel” offering a “better experience” for everyone. He notes that Nucleus ads don’t mention DNA or any details of how the scoring technique works. That’s not the point. In advertising, you sell the sizzle, not the steak. And in Nucleus’s ad copy, what sizzles is height, smarts, and light-colored eyes.

It makes you wonder if the ads should be permitted. Indeed, I learned from Sadeghi that the Metropolitan Transportation Authority had objected to parts of the campaign. The metro agency, for instance, did not let Nucleus run ads saying “Have a girl” and “Have a boy,” even though it’s very easy to identify the sex of an embryo using a genetic test. The reason was an MTA policy that forbids using government-owned infrastructure to promote “invidious discrimination” against protected classes, which include race, religion and biological sex.

Since 2023, New York City has also included height and weight in its anti-discrimination law, the idea being to “root out bias” related to body size in housing and in public spaces. So I’m not sure why the MTA let Nucleus declare that height is 80% genetic. (The MTA advertising department didn’t respond to questions.) Perhaps it’s because the statement is a factual claim, not an explicit call to action. But we all know what to do: Pick the tall one and leave shorty in the IVF freezer, never to be born.

This article first appeared in The Checkup, MIT Technology Review’s weekly biotech newsletter. To receive it in your inbox every Thursday, and read articles like this first, sign up here.

MIT Technology Review Explains: Let our writers untangle the complex, messy world of technology to help you understand what’s coming next. You can read more from the series here.

Weight-loss drugs have been back in the news this week. First, we heard that Eli Lilly, the company behind the drugs Mounjaro and Zepbound, became the first healthcare company in the world to achieve a trillion-dollar valuation.

Those two drugs, which are prescribed for diabetes and obesity respectively, are generating billions of dollars in revenue for the company. Other GLP-1 agonist drugs—a class that includes Mounjaro and Zepbound, which have the same active ingredient—have also been approved to reduce the risk of heart attack and stroke in overweight people. Many hope these apparent wonder drugs will also treat neurological disorders and potentially substance use disorders, too.

But this week we also learned that, disappointingly, GLP-1 drugs don’t seem to help people with Alzheimer’s disease. And that people who stop taking the drugs when they become pregnant can experience potentially dangerous levels of weight gain during their pregnancies. On top of that, some researchers worry that people are using the drugs postpartum to lose pregnancy weight without understanding potential risks.

All of this news should serve as a reminder that there’s a lot we still don’t know about these drugs. This week, let’s look at the enduring questions surrounding GLP-1 agonist drugs.

First a quick recap. Glucagon-like peptide-1 is a hormone made in the gut that helps regulate blood sugar levels. But we’ve learned that it also appears to have effects across the body. Receptors that GLP-1 can bind to have been found in multiple organs and throughout the brain, says Daniel Drucker, an endocrinologist at the University of Toronto who has been studying the hormone for decades.

GLP-1 agonist drugs essentially mimic the hormone’s action. Quite a few have been developed, including semaglutide, tirzepatide, liraglutide, and exenatide, which have brand names like Ozempic, Saxenda and Wegovy. Some of them are recommended for some people with diabetes.

But because these drugs also seem to suppress appetite, they have become hugely popular weight loss aids. And studies have found that many people who take them for diabetes or weight loss experience surprising side effects; that their mental health improves, for example, or that they feel less inclined to smoke or consume alcohol. Research has also found that the drugs seem to increase the growth of brain cells in lab animals.

So far, so promising. But there are a few outstanding gray areas.

Are they good for our brains?

Novo Nordisk, a competitor of Eli Lilly, manufactures GLP-1 drugs Wegovy and Saxenda. The company recently trialed an oral semaglutide in people with Alzheimer’s disease who had mild cognitive impairment or mild dementia. The placebo-controlled trial included 3808 volunteers.

Unfortunately, the company found that the drug did not appear to delay the progression of Alzheimer’s disease in the volunteers who took it.

The news came as a huge disappointment to the research community. “It was kind of crushing,” says Drucker. That’s despite the fact that, deep down, he wasn’t expecting a “clear win.” Alzheimer’s disease has proven notoriously difficult to treat, and by the time people get a diagnosis, a lot of damage has already taken place.

But he is one of many that isn’t giving up hope entirely. After all, research suggests that GLP-1 reduces inflammation in the brain and improves the health of neurons, and that it appears to improve the way brain regions communicate with each other. This all implies that GLP-1 drugs should benefit the brain, says Drucker. There’s still a chance that the drugs might help stave off Alzheimer’s in those who are still cognitively healthy.

Are they safe before, during or after pregnancy?

Other research published this week raises questions about the effects of GLP-1s taken around the time of pregnancy. At the moment, people are advised to plan to stop taking the medicines two months before they become pregnant. That’s partly because some animal studies suggest the drugs can harm the development of a fetus, but mainly because scientists haven’t studied the impact on pregnancy in humans.

Among the broader population, research suggests that many people who take GLP-1s for weight loss regain much of their lost weight once they stop taking those drugs. So perhaps it’s not surprising that a study published in JAMA earlier this week saw a similar effect in pregnant people.

The study found that people who had been taking those drugs gained around 3.3kg more than others who had not. And those who had been taking the drugs also appeared to have a slightly higher risk of gestational diabetes, blood pressure disorders and even preterm birth.

It sounds pretty worrying. But a different study published in August had the opposite finding—it noted a reduction in the risk of those outcomes among women who had taken the drugs before becoming pregnant.

If you’re wondering how to make sense of all this, you’re not the only one. No one really knows how these drugs should be used before pregnancy—or during it for that matter.

Another study out this week found that people (in Denmark) are increasingly taking GLP-1s postpartum to lose weight gained during pregnancy. Drucker tells me that, anecdotally, he gets asked about this potential use a lot.

But there’s a lot going on in a postpartum body. It’s a time of huge physical and hormonal change that can include bonding, breastfeeding and even a rewiring of the brain. We have no idea if, or how, GLP-1s might affect any of those.

How—and when—can people safely stop using them?

Yet another study out this week—you can tell GLP-1s are one of the hottest topics in medicine right now—looked at what happens when people stop taking tirzepatide (marketed as Zepbound) for their obesity.

The trial participants all took the drug for 36 weeks, at which point half continued with the drug, and half were switched to a placebo for another 52 weeks. During that first 36 weeks, the weight and heart health of the participants improved.

But by the end of the study, most of those that had switched to a placebo had regained more than 25% of the weight they had originally lost. One in four had regained more than 75% of that weight, and 9% ended up at a higher weight than when they’d started the study. Their heart health also worsened.

Does that mean that people need to take these drugs forever? Scientists don’t have the answer to that one, either. Or if taking the drugs indefinitely is safe. The answer might depend on the individual, their age or health status, or what they are using the drug for.

There are other gray areas. GLP-1s look promising for substance use disorders, but we don’t yet know how effective they might be. We don’t know the long-term effects these drugs have on children who take them. And we don’t know the long-term consequences these drugs might have for healthy-weight people who take them for weight loss.

Earlier this year, Drucker accepted a Breakthrough Prize in Life Sciences at a glitzy event in California. “All of these Hollywood celebrities were coming up to me and saying ‘thank you so much,’” he says. “A lot of these people don’t need to be on these medicines.”

This article first appeared in The Checkup, MIT Technology Review’s weekly biotech newsletter. To receive it in your inbox every Thursday, and read articles like this first, sign up here.

It has started to get really wintry here in London over the last few days. The mornings are frosty, the wind is biting, and it’s already dark by the time I pick my kids up from school. The darkness in particular has got me thinking about vitamin D, a.k.a. the sunshine vitamin.

At a checkup a few years ago, a doctor told me I was deficient in vitamin D. But he wouldn’t write me a prescription for supplements, simply because, as he put it, everyone in the UK is deficient. Putting the entire population on vitamin D supplements would be too expensive for the country’s national health service, he told me.

But supplementation—whether covered by a health-care provider or not—can be important. As those of us living in the Northern Hemisphere spend fewer of our waking hours in sunlight, let’s consider the importance of vitamin D.

Yes, it is important for bone health. But recent research is also uncovering surprising new insights into how the vitamin might influence other parts of our bodies, including our immune systems and heart health.

Vitamin D was discovered just over 100 years ago, when health professionals were looking for ways to treat what was then called “the English disease.” Today, we know that rickets, a weakening of bones in children, is caused by vitamin D deficiency. And vitamin D is best known for its importance in bone health.

That’s because it helps our bodies absorb calcium. Our bones are continually being broken down and rebuilt, and they need calcium for that rebuilding process. Without enough calcium, bones can become weak and brittle. (Depressingly, rickets is still a global health issue, which is why there is global consensus that infants should receive a vitamin D supplement at least until they are one year old.)

In the decades since then, scientists have learned that vitamin D has effects beyond our bones. There’s some evidence to suggest, for example, that being deficient in vitamin D puts people at risk of high blood pressure. Daily or weekly supplements can help those individuals lower their blood pressure.

A vitamin D deficiency has also been linked to a greater risk of “cardiovascular events” like heart attacks, although it’s not clear whether supplements can reduce this risk; the evidence is pretty mixed.

Vitamin D appears to influence our immune health, too. Studies have found a link between low vitamin D levels and incidence of the common cold, for example. And other research has shown that vitamin D supplements can influence the way our genes make proteins that play important roles in the way our immune systems work.

We don’t yet know exactly how these relationships work, however. And, unfortunately, a recent study that assessed the results of 37 clinical trials found that overall, vitamin D supplements aren’t likely to stop you from getting an “acute respiratory infection.”

Other studies have linked vitamin D levels to mental health, pregnancy outcomes, and even how long people survive after a cancer diagnosis. It’s tantalizing to imagine that a cheap supplement could benefit so many aspects of our health.

But, as you might have gathered if you’ve got this far, we’re not quite there yet. The evidence on the effects of vitamin D supplementation for those various conditions is mixed at best.

In fairness to researchers, it can be difficult to run a randomized clinical trial for vitamin D supplements. That’s because most of us get the bulk of our vitamin D from sunlight. Our skin converts UVB rays into a form of the vitamin that our bodies can use. We get it in our diets, too, but not much. (The main sources are oily fish, egg yolks, mushrooms, and some fortified cereals and milk alternatives.)

The standard way to measure a person’s vitamin D status is to look at blood levels of 25-hydroxycholecalciferol (25(OH)D), which is formed when the liver metabolizes vitamin D. But not everyone can agree on what the “ideal” level is.

Even if everyone did agree on a figure, it isn’t obvious how much vitamin D a person would need to consume to reach this target, or how much sunlight exposure it would take. One complicating factor is that people respond to UV rays in different ways—a lot of that can depend on how much melanin is in your skin. Similarly, if you’re sitting down to a meal of oily fish and mushrooms and washing it down with a glass of fortified milk, it’s hard to know how much more you might need.

There is more consensus on the definition of vitamin D deficiency, though. (It’s a blood level below 30 nanomoles per liter, in case you were wondering.) And until we know more about what vitamin D is doing in our bodies, our focus should be on avoiding that.

For me, that means topping up with a supplement. The UK government advises everyone in the country to take a 10-microgram vitamin D supplement over autumn and winter. That advice doesn’t factor in my age, my blood levels, or the amount of melanin in my skin. But it’s all I’ve got for now.

Earlier this week, the UK’s science minister announced an ambitious plan: to phase out animal testing.

Testing potential skin irritants on animals will be stopped by the end of next year, according to a strategy released on Tuesday. By 2027, researchers are “expected to end” tests of the strength of Botox on mice. And drug tests in dogs and nonhuman primates will be reduced by 2030. 

The news follows similar moves by other countries. In April, the US Food and Drug Administration announced a plan to replace animal testing for monoclonal antibody therapies with “more effective, human-relevant models.” And, following a workshop in June 2024, the European Commission also began working on a “road map” to phase out animal testing for chemical safety assessments.

Animal welfare groups have been campaigning for commitments like these for decades. But a lack of alternatives has made it difficult to put a stop to animal testing. Advances in medical science and biotechnology are changing that.

Animals have been used in scientific research for thousands of years. Animal experimentation has led to many important discoveries about how the brains and bodies of animals work. And because regulators require drugs to be first tested in research animals, it has played an important role in the creation of medicines and devices for both humans and other animals.

Today, countries like the UK and the US regulate animal research and require scientists to hold multiple licenses and adhere to rules on animal housing and care. Still, millions of animals are used annually in research. Plenty of scientists don’t want to take part in animal testing. And some question whether animal research is justifiable—especially considering that around 95% of treatments that look promising in animals don’t make it to market.

In recent decades, we’ve seen dramatic advances in technologies that offer new ways to model the human body and test the effects of potential therapies, without experimenting on humans or other animals.

Take “organs on chips,” for example. Researchers have been creating miniature versions of human organs inside tiny plastic cases. These systems are designed to contain the same mix of cells you’d find in a full-grown organ and receive a supply of nutrients that keeps them alive.

Today, multiple teams have created models of livers, intestines, hearts, kidneys and even the brain. And they are already being used in research. Heart chips have been sent into space to observe how they respond to low gravity. The FDA used lung chips to assess covid-19 vaccines. Gut chips are being used to study the effects of radiation.

Some researchers are even working to connect multiple chips to create a “body on a chip”—although this has been in the works for over a decade and no one has quite managed it yet.

In the same vein, others have been working on creating model versions of organs—and even embryos—in the lab. By growing groups of cells into tiny 3D structures, scientists can study how organs develop and work, and even test drugs on them. They can even be personalized—if you take cells from someone, you should be able to model that person’s specific organs. Some researchers have even been able to create organoids of developing fetuses.

The UK government strategy mentions the promise of artificial intelligence, too. Many scientists have been quick to adopt AI as a tool to help them make sense of vast databases, and to find connections between genes, proteins and disease, for example. Others are using AI to design all-new drugs.

Those new drugs could potentially be tested on virtual humans. Not flesh-and-blood people, but digital reconstructions that live in a computer. Biomedical engineers have already created digital twins of organs. In ongoing trials, digital hearts are being used to guide surgeons on how—and where—to operate on real hearts.

When I spoke to Natalia Trayanova, the biomedical engineering professor behind this trial, she told me that her model could recommend regions of heart tissue to be burned off as part of treatment for atrial fibrillation. Her tool would normally suggest two or three regions but occasionally would recommend many more. “They just have to trust us,” she told me.

It is unlikely that we’ll completely phase out animal testing by 2030. The UK government acknowledges that animal testing is still required by lots of regulators, including the FDA, the European Medicines Agency, and the World Health Organization. And while alternatives to animal testing have come a long way, none of them perfectly capture how a living body will respond to a treatment.

At least not yet. Given all the progress that has been made in recent years, it’s not too hard to imagine a future without animal testing.

This article first appeared in The Checkup, MIT Technology Review’s weekly biotech newsletter. To receive it in your inbox every Thursday, and read articles like this first, sign up here.

This week, we heard that Tom Brady had his dog cloned. The former quarterback revealed that his Junie is actually a clone of Lua, a pit bull mix that died in 2023.

Brady’s announcement follows those of celebrities like Paris Hilton and Barbra Streisand, who also famously cloned their pet dogs. But some believe there are better ways to make use of cloning technologies.

While the pampered pooches of the rich and famous may dominate this week’s headlines, cloning technologies are also being used to diversify the genetic pools of inbred species and potentially bring other animals back from the brink of extinction.

Cloning itself isn’t new. The first mammal cloned from an adult cell, Dolly the sheep, was born in the 1990s. The technology has been used in livestock breeding over the decades since.

Say you’ve got a particularly large bull, or a cow that has an especially high milk yield. Those animals are valuable. You could selectively breed for those kinds of characteristics. Or you could clone the original animals—essentially creating genetic twins.

Scientists can take some of the animals’ cells, freeze them, and store them in a biobank. That opens the option to clone them in the future. It’s possible to thaw those cells, remove the DNA-containing nuclei of the cells, and insert them into donor egg cells.

Those donor egg cells, which come from another animal of the same species, have their own nuclei removed. So it’s a case of swapping out the DNA. The resulting cell is stimulated and grown in the lab until it starts to look like an embryo. Then it is transferred to the uterus of a surrogate animal—which eventually gives birth to a clone.

There are a handful of companies offering to clone pets. Viagen, which claims to have “cloned more animals than anyone else on Earth,” will clone a dog or cat for $50,000. That’s the company that cloned Streisand’s pet dog Samantha, twice.

This week, Colossal Biosciences—the “de-extinction” company that claims to have resurrected the dire wolf and created a “woolly mouse” as a precursor to reviving the woolly mammoth—announced that it had acquired Viagen, but that Viagen will “continue to operate under its current leadership.”

Pet cloning is controversial, for a few reasons. The companies themselves point out that, while the cloned animal will be a genetic twin of the original animal, it won’t be identical. One issue is mitochondrial DNA—a tiny fraction of DNA that sits outside the nucleus and is inherited from the mother. The cloned animal may inherit some of this from the surrogate.

Mitochondrial DNA is unlikely to have much of an impact on the animal itself. More important are the many, many factors thought to shape an individual’s personality and temperament. “It’s the old nature-versus-nurture question,” says Samantha Wisely, a conservation geneticist at the University of Florida. After all, human identical twins are never carbon copies of each other. Anyone who clones a pet expecting a like-for-like reincarnation is likely to be disappointed.

And some animal welfare groups are opposed to the practice of pet cloning. People for the Ethical Treatment of Animals (PETA) described it as “a horror show,” and the UK’s Royal Society for the Prevention of Cruelty to Animals (RSPCA) says that “there is no justification for cloning animals for such trivial purposes.” 

But there are other uses for cloning technology that are arguably less trivial. Wisely has long been interested in diversifying the gene pool of the critically endangered black-footed ferret, for example.

Today, there are around 10,000 black-footed ferrets that have been captively bred from only seven individuals, says Wisely. That level of inbreeding isn’t good for any species—it tends to leave organisms at risk of poor health. They are less able to reproduce or adapt to changes in their environment.

Wisely and her colleagues had access to frozen tissue samples taken from two other ferrets. Along with colleagues at not-for-profit Revive and Restore, the team created clones of those two individuals. The first clone, Elizabeth Ann, was born in 2020. Since then, other clones have been born, and the team has started breeding the cloned animals with the descendants of the other seven ferrets, says Wisely.

The same approach has been used to clone the endangered Przewalski’s horse, using decades-old tissue samples stored by the San Diego Zoo. It’s too soon to predict the impact of these efforts. Researchers are still evaluating the cloned ferrets and their offspring to see if they behave like typical animals and could survive in the wild.

Even this practice is not without its critics. Some have pointed out that cloning alone will not save any species. After all, it doesn’t address the habitat loss or human-wildlife conflict that is responsible for the endangerment of these animals in the first place. And there will always be detractors who accuse people who clone animals of “playing God.” 

For all her involvement in cloning endangered ferrets, Wisely tells me she would not consider cloning her own pets. She currently has three rescue dogs, a rescue cat, and “geriatric chickens.” “I love them all dearly,” she says. “But there are a lot of rescue animals out there that need homes.”

This article first appeared in The Checkup, MIT Technology Review’s weekly biotech newsletter. To receive it in your inbox every Thursday, and read articles like this first, sign up here.