Embryonic Human Beings
by Robert P. George
McCormick Professor of Jurisprudence
Princeton University

A human embryo is not something different in kind from a human being, like a rock, or a potato, or a rhinoceros. A human embryo is a whole living member of the species Homo sapiens in the earliest stage of his or her natural development. Unless severely damaged or denied or deprived of 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 (zygote) and develops, if all goes well, into adulthood many years later.

A human embryo (like a human being in the fetal, infant, child, or adolescent stage) is not properly classified as a “pre-human” organism with the mere potential to become a human being. No human embryologist or textbook in human embryology known to me presents, accepts, or remotely contemplates such a view. The testimony of all leading embryology textbooks is that a human embryo is—already and not merely potentially—a human being. His or her potential, assuming a sufficient measure of good health and a suitable environment, is to develop by an internally directed process of growth through the further stages of maturity on the continuum that is his or her life. The rest-Excellent!