Even for persons who hold to the ethical acceptance of abortion practices in general, questions of detail often arise. If you assume the distinction between the physical human organism alone and the person that is associated with that organism, then you must face the question of whether it is permissible to abort a fetus if the corresponding person has come into being. We take the position that the abortion of a fetus that has achieved this level of development should be (...) declared unethical except in special circumstances. Our purpose here is to identify the point in the development of the fetus that serves as the marker for this level. (shrink)

I argue that contraception is morally wrong but that periodic abstinence (or natural family planning) is not. Further, I argue that altered nuclear transfer—a proposed technique for creating human stem cells without destroying human embryos—is morally wrong for the same reason that contraception is. Contrary to what readers might expect, my argument assumes nothing about the morality of cloning or abortion and requires no premises about God or natural teleology. Instead, I argue that contraception and altered nuclear transfer are morally (...) wrong because they fail to treat humanity as an inviolable end. (shrink)

In this essay, I attempt to provide answers to the following four queries concerning the metaphysics of early human embryogenesis. (1) Following its first cellular fission, is it coherent to claim that one and only one of two “blastomeric” twins of a human zygote is identical with that zygote? (2) Following the fusion of two human pre-embryos, is it coherent to claim that one and only one pre-fusion pre-embryo is identical with that postfusion pre-embryo? (3) Does a live human being (...) come into existence only when its brain comes into existence? (4) At implantation, does a pre-embryo become a mere part of its mother? I argue that either if things have quidditative properties or if criterialism is false, then queries (1) and (2) can be answered in the affirmative; that in light of recent developments in theories of human death and in light of a more “functional” theory of brains, query (3) can be answered in the negative; and that plausible mereological principles require a negative answer to query (4). (shrink)