Some excerpts from Ryan T. Anderson's review of Frank Beckwith's new book, Defending Life: A Moral and Legal Case Against Abortion Choice for National Review:
He begins by marshaling medical embryology to show that "from a strictly scientific point of view . . . an individual human life begins at conception." Whereas sperm and egg each contain half of the genetic code (23 chromosomes) and are parts of larger organisms (the parents), the one-celled zygote "is a new, although tiny, individual with a human genetic code with its own genomic sequence (with 46 chromosomes), which is neither her mother's nor her father's. From this point until death no new genetic information is needed to make the unborn entity an individual human being." Beckwith responds to common objections, noting that high rates of natural embryo loss no more disprove the humanity of embryos than high rates of infant mortality do that of infants; that early-embryo twinning does no more to undermine the unity of the embryo prior to twinning than cutting a flatworm in half (forming two flatworms) does to its unity prior to separation; and that while a human embryo doesn’t look like an adult, it "does look exactly like a human ought to look at this stage of her development."
If embryos and fetuses are human beings (which the science compels reasonable people to acknowledge), do they have a right to life? Some, like David Boonin of the
Beckwith rejects these arguments because they rest on a faulty understanding of the human person, undermine human equality, and produce morally repugnant conclusions. . . .
"The human being is a particular type of substance -- a rational moral agent -- that remains identical to itself as long as it exists, even if it is not . . . currently able to immediately exercise these activities." We are valuable in virtue of the sort of thing (the substance) we are -- human beings, with basic root capacities for personal acts. Since a substance cannot come in degrees, we are all equally human beings and thus equally valuable.