Beyond naming: embryo models and the importance of public dialogue

Who decides what to name something new in science like “human embryo models”?

Parmin Sedigh, human embryo models
Author Parmin Sedigh.

Also, not to get too philosophical right off the bat, but what is the point of a name?

It’s about a shared understanding of what we’re talking about. But, very often, both out in the world and in the various fields of science, it’s not quite so simple.

Words are wrought with unsaid connotations that can sway or even taint the way they’re used and their meanings. This is especially true for contentious topics, such as naming something some of the general public take issue with: human embryo models.

A “human embryo model” is a 3D collection of cells, usually grown from stem cells in a lab, that bears some striking similarities to a human embryo.

human embryo models, mouse embryo models.
Mouse embryo models or ETX structures. These are named after the three cell types included in the model: embryonic stem cells (E)—which, in normally fertilized embryos, eventually give rise to all cells in the body—as well as trophoblast (T) and extra-embryonic endoderm (X) stem cells which support the embryo’s development. These structures exhibit features seen during gastrulation. Yellow denotes embryonic, magenta denotes trophoblast, and blue-green denotes extra-embryonic endoderm stem cells. Source: Berna Sozen, Magdalena Zernicka-Goetz lab.

The logic behind naming human embryo models

“Human embryo model” is the name the ISSCR wants us to use. But when postgastrulation embryo models grabbed the attention of mainstream media in 2022, many news articles were quick to use the term “synthetic embryo” instead, much to the chagrin of scientists. (Of note, the use of the term began before that, such as at a scientific meeting in 2016).

They’re not synthetic or embryos, came calls from scientists, and rightfully so. Does this distinct ultimately matter, though? Many are firmly in the “yes” camp. Having a name that accurately captures these models is important both for communication with the public and for setting appropriate regulations, argue Janet Rossant and Amander Clark, who are co-leading the new Embryo Models Working Group at the ISSCR. In fact, they find the “synthetic” part of the name disrespectful to donors and believe it creates a perception of “scientist-as-Creator.” And I tend to agree.

How aware is the public anyway?

Yet, this is somewhat reminiscent of a related argument I’ve heard scientists make before, about the 14-day rule for culturing embryos in vitro. When the ISSCR recommended a cautious and step-by-step approach to extending this limit, some opposed this, saying that the 14-day rule was important because it gave the public more confidence in scientists (though, admittedly, this specific argument was made by only a few). It let them know that scientists were careful and thoughtful in conducting potentially contentious research. Let’s take a step back, and think about it though. Very few members of the public know about the 14-day rule. How can you feel comforted by a rule you don’t know exists?

Bringing it back to the embryo models, it’s absolutely true that the synthetic embryo name can scare the public and overstate how good the models are. For members of the public who only read the headlines, this difference in naming can change their views. But the real battle begins once they click on the article and start reading. Does the writer do a good job of capturing the state of the field and what’s actually going on? Do they use the term “embryo model” and then proceed to fearmonger anyway? The way writers discuss research is just as important as the names they use for scientific matters. Put differently, does the public care if we call these models “synthetic embryos” or “embryo models” if they don’t agree—or understand—the field and premise in the first place?

Challenges for the media and researchers in this arena

As an aside, I’d like to take a moment to acknowledge the difficult task ahead for journalists who cover these topics. Scientists have every right to be upset when science isn’t communicated accurately. But staying true to the science while discussing complex topics—and grabbing people’s attention—is hard. 

Let’s take a webinar hosted by Insoo Hyun, Director of Research Ethics of the Center for Bioethics at Harvard Medical School, with the Museum of Science in Boston as an example. During the webinar, Hyun mentioned that he wanted to find a way to use the term “synthetic embryo” in the title of this public-facing webinar without condoning the use of the term. He ultimately landed on the name, Don’t Call Them ‘Synthetic Embryos’: How Human Embryo Models Could Help Advance Bioscience, getting the best of both worlds.

This difficulty doesn’t mean journalists should use whatever term generates the most clicks, but that scientists could do well by having open, two-sided conversations with them about what terms best capture the science while realizing the difficulties journalists face. Another challenge is that many stem cell scientists are unwilling to talk to the media at all, perhaps in part because they don’t feel comfortable in that role.

Human embryo model regulation

Let’s move over to the regulatory aspect of the argument against “synthetic embryos” now. When these models entered mainstream discussion, many of the old (perhaps unhealed) wounds around embryo research regulation opened once more, and new wounds emerged too. When is an embryo model close enough to a fertilized embryo to have the same protections? How do scientists validate how accurately these models capture what happens in vivo without crossing the ethical line? Should regulations for these models be any different than the ones for embryonic stem cell lines? These are very challenging questions both for researchers and regulators.

Some have argued that calling these models “embryos”—without the “model” qualifier—obfuscates their rightful purpose, which is to use these models to better understand human development, not to replace it. It is difficult to disagree with the fact that the term “embryo” unsettles many regulatory bodies and may lead to regulations that hinder the research without protecting much of anything. Politics and religion can come into play too. The “scientist-as-Creator” connotation discussed above would likely lead to regulations that don’t fit the true state of the field. Here is another sense where using the term “embryo models” is critical.

Ultimately, Nienke de Graeff, assistant professor at the Department of Medical Ethics & Health Law at Leiden University Medical Centre, and colleagues perhaps said it best:

“More pivotal than the naming of embryo models are the questions that underpin the linguistic discourse: what status should these entities be attributed, and what ethical boundaries should govern our actions with them?” 

The naming surely matters, but not as much as discussions with the public that help resolve the most pressing issue in many people’s minds: How will this help me?

About the author:

Parmin Sedigh is a second-year undergraduate student at the University of Toronto who enjoys writing about the stem cell field and anything science-related.

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