The new biology and the question of personhood: implications for abortion

Opposition to abortion is based in part on the assumption that personhood is achieved at or shortly after fertilization of the egg. This interpretation of personhood arises from a contemporary application of the ancient doctrine of preformationism, a doctrine which holds that there is a preformed individual, in an ontological sense, within the developing entity. The assumption that the fertilized egg is unique in its capacity to develop into a human being is at least in part responsible for the opinions of those opposed to abortion. Yet, the uniqueness of the zygote in its capacity to develop into an adult organism is qualified by the discovery that development may be possible in a number of other ways. Consideration of the phenomena of cloning, parthenogenesis and chimerism can relieve moral ambiguity about abortion and may reduce opposition to that practice.