The anti-choice advocates are always citing a handful of embryologists in order to claim that scientists say human life begins at fertilization. The one fellow who is always getting cited in these claims is Keith L. Moore, a very familiar name in embryology circles, because he wrote several introductory texts on human embryology. I thought I would quote what Moore and Persaud actually wrote in the 4th edition of Before We Are Born: Essentials of Embryology and Birth Defects in 1993 (this text has been around since 1974, so it really has trained a generation in medical embryology, and there is also a 2012 edition, which I don’t own…it’s a bit on the elementary side for my interests).
The section on the first week of human development begins:
Human development begins at conception or fertilization when a male gamete or sperm fuses with a female gamete or ovum to form a zygote (Br. zygotos, yoked together). This highly specialized, totipotent cell is the primordium of a new human being. By birth the zygote has given rise to millions of cells [that's an underestimate --pzm]. Although large, the zygote is just visible to the unaided eye. It contains chromosomes and genes (units of genetic information) derived from the mother and father.
Odd…it doesn’t say we have a human being at fertilization, but instead says we have a totipotent cell that is a primordium that will become a human being.
By golly, I think the anti-choicers stretch the truth as much as creationists do!