As I was preparing for the upcoming issue of ProVita, I ran across this book on Amazon: Embryos Under the Microscope: Ths Diverging Meanings of Life, by Jane Maienschein. The author claims to be giving a history of the human knowledge of embryology so that ethical decisions can be based on accurate scientific information. What I found interesting was this assertion in the book description:
Biologists confirmed that embryos are living organisms undergoing rapid change and are not in any sense functioning persons. They do not feel pain or have any capacity to think until very late stages of fetal development.
As you can see, the embryo is excluded from personhood based on function, They can’t feel pain or think. This, of course, is not a biological determination, but a philosophical one. Biologists don’t determine who is a person and who is not. And philosophers aren’t unanimous that function is the basis for determining personhood. Others look to a more comprehensive and precise criterion, active potency. The human organism has the active potency to develop functions such as sensitivity to pain and cognition from fertilization.