The Metaphysical Status of the Placenta

The metaphysical status of the placenta has bearing on several ongoing discussions within Catholic moral theology. Numerous bioethicists and theologians have touched on this topic briefly, but to date no robust metaphysical argument appears in the literature. The authors aim to provide such an analysis. First, they provide an overview of the existing literature on the topic. Second, they briefly review the anatomy and physiology of the placenta. Third, they provide metaphysical and biological reasons why the placenta cannot be a part of the fetus, a part of the mother, simultaneously a part of both, the border at which mother and fetus meet, or a separate individual substance. Finally, they provide reasons that support their claim that the placenta is a quasi-substance that exists in symbiosis with mother and child. National Catholic Bioethics Quarterly 14.2 : 295–333.