Perspectives in Biology and Medicine 48:2 (Spring 2005), with Alfonso Gómez-Lobo. First published as "Statement of Professor George" in Leon R. Kass (ed.), Human Cloning and Human Dignity: The Report of the President's Council On Bioethics (Public Affairs, 2002), pp. 294-306; and Human Cloning and Human Dignity: An Ethical Inquiry (The President’s Council on Bioethics, 2002).
The subject matter of Human Cloning and Human Dignity (President’s Council 2002) is the production of a human embryo by means of somatic cell nuclear transfer (SCNT) or similar technologies. Just as fertilization, if successful, generates a human embryo, cloning produces the same result by combining what is normally combined and activated in fertilization, that is, the full genetic code plus the ovular cytoplasm. Fertilization produces a new and complete, though immature, human organism. The same is true of successful cloning. Cloned embryos therefore ought to be treated as having the same moral status as other human embryos.
A human embryo is a whole living member of the species Homo sapiens in the earliest stage of his or her natural development. Unless denied a suitable environment, an embryonic human being will by directing its own integral organic functioning develop himself or herself to the next more mature developmental stage, i.e., the fetal stage. The embryonic, fetal, infant, child, and adolescent stages are stages in the development of a determinate and enduring entity—a human being—who comes into existence as a single cell organism and develops, if all goes well, into adulthood many years later.
Human embryos possess the epigenetic primordia for self-directed growth into adulthood, with their determinateness and identity fully intact. The adult human being that is now you or me is the same human being who, at an earlier stage of his or her life, was an adolescent, and before that a child, an infant, a fetus, and an embryo. Even in the embryonic stage, you and I were undeniably whole, living members of the species Homo sapiens. We were then, as we are now, distinct and complete (though in the beginning we were, of course, immature) human organisms; we were not mere parts of other organisms.
Consider the case of ordinary sexual reproduction. Plainly, the gametes whose union brings into existence the embryo are not whole or distinct organisms. They are functionally (and not merely genetically) identifiable as parts of the male or female (potential) parents. Each has only half the genetic material needed to guide the development of an immature human being toward full maturity. They are destined either to combine with an oocyte or spermatozoon to generate a new and distinct organism, or simply die. Even when fertilization occurs, they do not survive; rather, their genetic material enters into the composition of a new organism.
But none of this is true of the human embryo, from the zygote and blastula stages onward. The combining of the chromosomes of the spermatozoon and of the oocyte generates what every authority in human embryology identifies as a new and distinct organism. Whether produced by fertilization or by SCNT or some other cloning technique, the human embryo possesses all of the genetic material needed to inform and organize its growth. Unless deprived of a suitable environment or prevented by accident or disease, the embryo is actively developing itself to full maturity. The direction of its growth is not extrinsically determined, but is in accord with the genetic information within it. The human embryo is, then, a whole (though immature) and distinct human organism—a human being.
If the embryo were not a complete organism, then what could it be? Unlike the spermatozoa and the oocytes, it is not a part of the mother or of the father. Nor is it a disordered growth such as a hydatidiform mole or teratoma. (Such entities lack the internal resources to actively develop themselves to the next more mature stage of the life of a human being.) Perhaps someone will say that the early embryo is an intermediate form, something that regularly emerges into a whole (though immature) human organism but is not one yet. But what could cause the emergence of the whole human organism, and cause it with regularity? It is clear that from the zygote…