What Are Cell-based Embryo Models and Should We Be Worried?

Over the past decade, scientists have been able to use cells to create models that mimic stages of early human embryo development within the first few weeks after fertilization. These entities are referred to by many terms, including embryoids (as described in the 2021 paper co-authored by fellow Kirstin R.W. Matthews). As research progresses and embryoids become more sophisticated, they will gain more features and more closely resemble human embryos. This raises ethical and policy challenges that must be addressed. 

To understand the challenges that this research raises, Center for Health and Biosciences experts Ana S. Iltis and Kirstin R.W. Matthews reviewed the literature related to human embryoid research to determine ethical and policy concerns and questions raised. Their review is published in the paper “Ethical, Legal, Regulatory, and Policy Issues Concerning Embryoids: A Systematic Review of the Literature.”

From 2016 to 2022, 56 papers that focused on human embryoid ethical and policy questions were published. The concerns and questions raised fell into four broad categories: 

1. Justifications for and/or benefits of conducting embryoid research.
2. Ethical significance or moral status of human embryoids.
3. Permissible uses of human embryoids.
4. Regulatory and oversight challenges associated with human embryoids research.

The papers included in Iltis and Matthews' review generally discussed the potential benefits of increased knowledge on early embryo development through embryoid research. However, there were concerns related to the moral status of these entities created in a lab, especially as they become more sophisticated, develop neurologically, and more closely resemble human embryos.

There were also significant discussions related to permissible uses and questions regarding what research should be limited, such as how long developmentally embryoids should be allowed to grow and whether the growing of embryoids in a woman’s uterus should be banned. Finally, there were a series of questions about how embryoids fit into existing policies, what new policies should be developed, and the importance of involving the public in policy development.

Analyzing the full range of issues associated with embryoid research is a critical step toward fostering more robust ethical, legal, and social implications research in this emerging area and toward developing appropriate oversight.