Earlier this summer, when scientists revealed they’re now able to create blobs of stem cells in the lab that self-organize into the same sorts of structures embryos themselves build during those first few weeks, it blasted wide open whatever ideas of the embryo we used to have. Were these structures embryo models, as some scientists named them, or something approaching actual embryos? How would anyone know when that line had been crossed?
In a perspective published [August 17] in Cell, [developmental biologist Nicolas Rivron] and an international group of leading luminaries in the fast-moving field of synthetic embryology — or “stembryology,” as it’s sometimes called — argue that these latest scientific advances justify a new definition for the human embryo that’s rooted not in how it was made, but in what it can become.
…
He and his co-authors proposed that embryos be defined as “a group of human cells supported by elements fulfilling extra-embryonic and uterine functions that, combined, have the potential to form a fetus.”
In other words, embryo models could be considered embryos if they have the potential to survive to the equivalent of eight weeks into a pregnancy — a stance at odds with a statement issued earlier this year by an international group of stem cell scientists.
