Synthetic human embryos could allow for research beyond the 14-day limit, but this raises ethical questions

On June 14, 2023, developmental biologist Magdalena Żernicka-Goetz presented her research on creating human embryos using stem cells at the 2023 annual meeting of the International Society for Stem Cell Research (ISSCR).

This research could increase our understanding of human development and genetic disorders, help us learn how to prevent early miscarriages, lead to improvements in fertility treatment, and — perhaps — eventually allow for reproduction without using sperm and eggs.

Beyond the limits
Synthetic human embryos — also called embryoid bodies, embryo-like structures or embryo models — mimic the development of “natural human embryos,” those created by fertilization. Synthetic human embryos include the “cells that would typically go on to form the embryo, placenta and yolk sac, and develop to form the precursors of germ cells (that will form sperm and eggs).”

Though research involving natural human embryos is legal in many jurisdictions, it remains controversial. For some people, research involving synthetic human embryos is less controversial because these embryos cannot “develop to the equivalent of postnatal stage humans.” In other words, these embryos are non-viable and...