June 23, 2023, by Brigitte Nerlich

Synthetic embryos: Science, communication, clarification

Earlier in the month (June, 2023) I saw some headlines saying things like “Scientists say first synthetic human ’embryo’ created” or “First reported synthetic human embryo sparks ethical concerns, creates questions” or “Synthetic human embryos created for first time using no eggs or sperm”.

These headlines appeared soon after an exclusive article on the matter had been published in The Guardian under the byline of Hannah Devlin, the newspaper’s science correspondent: “Synthetic human embryos created in groundbreaking advance“.

That was all very interesting, but soon I began to ask myself: Were the embryos a first? Were they synthetic? Were they embryos? Answers to these questions are important in the context of public understanding of science, science communication, bioethics and regulation; especially in light of headlines like these on Breitbart News: “Welcome to Transhumanist Hell: Scientists Create ‘Synthetic Human Embryo’”.

I am not an expert on these matters, but I soon found out that there are quite a few people who are. In this post I just want to list a few of their contributions so that readers have some resources to navigate this issue if they want to, especially since soon after the sensationalist reporting on this matter other reports appeared, saying for example that “Cambridge scientists claiming to have created synthetic human embryos have been accused of irresponsibly boasting about their work in a moment reminiscent of one of science’s biggest scandals”, such as that surrounding the Chinese researcher He Jiankui and his ‘Crispr babies’ (The Telegraph, 15 June). Oh dear, I thought.

The research has not yet appeared in a peer-reviewed journal. The Guardian‘s announcement came after “Magdalena Zernicka-Goetz of Cambridge University and the California Institute of Technology described her team’s work at the International Society for Stem Cell Research’s annual meeting in Boston” on Wednesday 14 June. “On Thursday, the team of Jacob Hanna at the Weizmann Institute of Science in Israel published a pre-print study detailing their own work on stem cell-based human embryo models. The Zernicka-Goetz team then quickly published a pre-print of their own, giving more information. Other labs based in China and the United States followed suit, releasing pre-prints late last week.” (Aljazeera, 20 June) (Hanna’s preprint here. Zernicka-Goetz’s here)

I can’t describe all the debates and ramifications in this post; instead I’ll provide some quick resources for those intersted in the words ‘first’, ‘synthetic’ and ’embryo’. As usual, language matters in science communication.


In an article in Nature (News Explainer), Philip Ball, a science writer who has written widely about these matters, sets out why the word ‘first’ is inappropriate and explores scientific, ethical and regulatory issues around this step forward in embryo modelling. In a tweet Ball reminded people that human embryo models are not that new and pointed to a 2021 article in Nature on this matter by Sandeep Ravindran.


Ildem Akerman, Associate Professor in Functional Genomics and Diabetes UK RD Lawrence Fellow, University of Birmingham, told the Science Media Centre: “it’s important to clarify that although the authors referred to them as ‘synthetic’ embryos, these cell clusters are not truly synthetic in the sense that they are created from scratch. Instead, they are derived from living stem cells that originate from an embryo. Essentially, what scientists do is cultivate a single stem cell and encourage its growth into an organized group of cells that, in theory, possess the potential to develop into an implantable embryo.”

And in this short interview for the Radio 4 Today programme Julian Hitchcock, an expert on the regulation of regenerative and reproductive medicine, genomics, gene-editing and embryo research, also points out that these embryos are actually not ‘synthetic’.

What’s tricky about these structures, synthetic or not, is the following: “While UK law prohibits the implantation of these synthetic embryos into a human womb, they are not actually considered to be embryos and as such are not covered by the Human Fertilisation and Embryology Act.” (BMJ, 19 June)


The most thorny questions therefore surrounds the issue of whether or not the blobs or masses of cells etc. created in the lab are embryos or should be called embryos. Many responsible journalists used the phrase ’embryo models’ instead of just ’embryo’. Some went further.

As Aljazeera reported: “Researchers have pushed back against media reports calling the clumps of cells ‘synthetic embryos’, saying they are neither strictly synthetic, having grown from stem cells, nor should they be considered embryos.”

Some even doubt whether the phrase ’embryo model’ rather than just embryo is correct. Such questions have of course direct implications for bioethics and regulation. You can only regulate something if you know what it is and if you can talk about it.

‘Embryo-like structures’ seems to be the right expression, and has been for a while.

Ethics and regulation

On June 13, just before things hotted up, Philip Ball published an article on ethics and regulation for Quanta Magazine, building on an article he had written for Nature in May entitled “Human embryo science: Can the world’s regulators keep pace?” A very good question, to which I might add my own: Can responsible regulation keep pace with responsible research and innovation?

On 16 June the bioethicist Kathryn McKay published an article for The Conversation joining a conversation on the matter of ethics, morals and regulation. Two months earlier the bioethics expert had written an article about the potential for/likelihood of human babies from stem cells, published also in The Conversation. At the same time Jessica Hamzelou, a science journalist and editor specialising in health, medical science and biotechnology, had provided an overview of ethical and regulatory conundrums relating to using stem cells to make embryos in an article for MIT Technology Review.

And finally, on 21 June, Anjana Ahuja, who writes on science issues for the Financial Times reflected “on the ethical catch-22 with synthetic embryos: the closer they are to human ones, the more scientifically useful for studying #Pregnancy loss – but also more ethically problematic” in an article entitled “Synthetic embryos create an ethical catch-22″… And there might be many more articles I haven’t seen.

Haha, while I was writing this paragraph, I saw, via a Tweet by Roland Pease, the presenter of the programme, that Science in Action (BBC World Service) will be broadcasting (has done so, by the time this post goes out) a “stembryo special, w @ZernickaGoetz @jacob_hanna @HankGreelyLSJU @AndSBernardo & @Cam_Repro‘s Sarah Franklin tackles the science & ethics of the new claims”. Sarah Franklin is a longstanding expert on this issue, given that she has “substantially contributed to the fields of feminism, gender studies, cultural studies and the social study of reproductive and genetic technology”.

Science communication

I bet that there are many more articles and programmes out there reflecting on the communicative, legal, ethical and regulatory aspects of this probably premature announcement of a ‘breakthrough’ in embryo research. It’s gratifying to see how quickly science communicators went to work on dispelling myths and misunderstandings. It’s a shame though that eloquent articles published in Nature, Quanta Magazine or The Conversation were not picked up by The Guardian to ensure wider dissemination and broaden the discussions started in and by the first article.

If you want to explore these issues further, you might also want to go to the Science Media Centre where you can find expert reactions to the first announcement and the preprints.

PS 18 August, 2023. Here is a useful article by Philip Ball on what it would take to redefine the ’embryo’. And here are some thought by Naomi Moris from The Crick on when an embryo model becomes an embryo.

PS 18 May, 2024. Here is a useful thread by Jacob Hanna on all the terminological complications….And this by John Wallingford is also worth reading if you want to go deeper into the history and philosophy of embryology!!!

Image: Didactic model of human embryonic development; Creator Wagner Souza e Silva (Wikimedia Commons)

Posted in science communication