Skip to Content
Biotechnology and health

The wild race to improve synthetic embryos

Scientists are feuding over who's closest to the real thing.

gloved hands hold a glass vial of synthetic embryos
A vial full of "synthetic" mouse embryos made from stem cells, as seen in a 2022 photo taken in Israel.Ilia Yefimovich/picture-alliance/dpa/AP Images

This article is from The Checkup, MIT Technology Review's weekly biotech newsletter. To receive it in your inbox every Thursday, sign up here. This week, Antonio Regalado, senior editor for biomedicine is filling in for Jess Hamzelou.

Something journalists and scientists have in common is that they hate getting scooped. And it’s especially annoying when the news is “fake.”

But that’s what happened at the meeting of the International Society for Stem Cell Research in Boston last week when The Guardian newspaper blasted out news of a sensational “breakthrough.”

The publication claimed that a researcher named Magdalena Zernicka-Goetz, based at the University of Cambridge and Caltech, had created “synthetic human embryos” using stem cells as the starting point.

The reason the Guardian story annoyed me is that this idea isn’t so new. The amazing fact that stem cells will self-organize into structures sharing features with real embryos has been known and studied for several years, as we first reported in 2017.

Since then, several labs have been in a competitive race to make these “embryo models” more complete, more realistic, and ever more like bona fide embryos, complete with placenta tissue.

What irked scientists was that Zernicka-Goetz appeared to claim to have finished the race—but did so in the media, without providing any scientific proof. 

A Spanish scientist, Alfonso Martinez Arias, quickly launched a campaign on Twitter in which he fiercely denounced “fake news” and “#posttruth” science. In reality, he says, Zernicka-Goetz had produced blobs he calls “weakly organized masses of cells” with limited similarity to real embryos.

The twist in the story is that there actually was a breakthrough, but it came from a different lab. Shortly after the Guardian story came out, Jacob Hanna, a scientist based in Israel, posted a preprint paper describing extremely realistic synthetic embryo models that were grown to a stage of around 14 days.

According to Arias, Hanna “showed exactly” what Zernicka-Goetz had claimed “but hadn’t done.” 

For Zernicka-Goetz’s part, she later said on Twitter that her lab’s creations “are not real embryos.” “In response to recent media on my group’s research, I would like to clarify that our goal was not to make headlines but to share our research with the community. We cannot control how the news reports our discoveries, but we are grateful for the interest & constructive comments,” she also said.  

It’s not unheard-of for scientists to try to scoop one another. But what’s troubling about last week’s hijinks (nicely covered by the Spanish newspaper El País) is that we’re talking about lab creations that could eventually count as real human embryos.

“We need a defined framework, but instead what we see here is a fairly wild race between labs,” one journal editor told me during the ISSCR meeting. “The overarching question is: How far do they go, and where do we place them in a legal-moral spectrum? How can we endorse working with these models when they are much further along than we were two years ago?”

So where will the race lead? Most scientists say the point of mimicking the embryo is to study it during the period when it would be implanting in the wall of the uterus. In humans, this moment is rarely observed. But stem-cell embryos could let scientists dissect these moments in detail.

Yet it’s also possible that these lab embryos turn out to be the real thing—so real that if they were ever transplanted into a person’s womb, they could develop into a baby.

So far, scientific organizations like the ISSCR say transplanting a synthetic human embryo should be forbidden. But technical advances suggest that it could be possible to incubate them outside of the womb entirely. Not only are scientists able to grow embryos in the lab for longer periods, but on the other end of development, premature babies can be kept alive earlier and earlier.

“You’re digging a tunnel to meet in the middle, and I see no reason why that would stop,” Carlos Gantner, a member of the Zernicka-Goetz team, told me when I caught up to him at the meeting.“There is no reason you couldn’t reproduce this way.”

But would you want to? Strangely enough, any person who developed from a synthetic embryo would be a clone—a clone of whoever’s cells were used to make the embryo in the first place.

If you are looking for a clone army, like in Star Wars, this is the technology you’ll want to be considering.

Read more from Tech Review’s archive:

A startup company wants to make synthetic human embryos and harvest their tiny organs for use in transplant medicine. The idea is to use the embryo models as “3D bioprinters,” as I wrote last year.

Can a synthetic embryo lead to a live birth? Researchers in China gave it a shot in monkeys, but it didn’t work, Jessica Hamzelou reported in April.

One of the top reasons someone would try cloning a person would be to replace a child who died. In 2018, I interviewed a mother who was drawn into a mysterious dog cloning project after her daughter died by suicide.

Another thing:

Police broke up an overcrowded scientific presentation on rejuvenation technology. The brouhaha in Boston signaled intense interest around Altos Lab, a company established to explore age reversal in animals and human cells. Reversing the life process would be the “ultimate feat” for biotech engineers. (MIT Technology Review)

From around the web:

Patient-zero rumors. News reports say the US believes three key scientists doing risky coronavirus research at the Wuhan Institute of Virology fell ill with a respiratory illness in 2019, feeding speculation that covid-19 was the result of a laboratory accident. (WSJ) The Biden Administration missed a deadline to declassify all that it knows about the pandemic’s origin. (NYT)

We’re used to hearing about dramatic gene therapy cures … and so are stock investors. That could be why shares of the gene therapy company Uniqure tumbled by 40% after its effort to treat Huntington’s disease gave equivocal results. The genetic disease is fatal, so patients are desperate for options and still hope the experimental treatment will prove useful. (Evaluate)

In other investment news, the biotech industry is awash with questionable trades. Executives and investors are making “superbly well-timed trades” that net them hundreds of thousands or millions of dollars. Some look suspicious. (ProPublica)

Organs can be stored by “vitrifying” them into a glass-like state. Researchers say vitrified organs from rats have been thawed and successfully transplanted into recipient animals—a “historic” development for the field. (STAT)

Deep Dive

Biotechnology and health

Google helped make an exquisitely detailed map of a tiny piece of the human brain

A small brain sample was sliced into 5,000 pieces, and machine learning helped stitch it back together.

That viral video showing a head transplant is a fake. But it might be real someday. 

BrainBridge is best understood as the first public billboard for a hugely controversial scheme to defeat death.

The effort to make a breakthrough cancer therapy cheaper

CAR-T cells could revolutionize the treatment of a wide variety of diseases, if only we can make them cheaper.

Beyond Neuralink: Meet the other companies developing brain-computer interfaces

Companies like Synchron, Paradromics, and Precision Neuroscience are also racing to develop brain implants

Stay connected

Illustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at customer-service@technologyreview.com with a list of newsletters you’d like to receive.