It is important to know as precisely as possible when a human being comes into existence. This can occur in ordinary circumstances after sexual intercourse. It can also occur in a nonsexual manner by various types of cloning and genetic engineering techniques and in naturally occurring monozygotic identical twining in vivo. Many scientists and physicians, in an effort to avoid being accused of abuse of human embryos in their research and in the practice of abortion, have falsified the facts about (...) human conception for many years throughout the world, creating moral confusion and error. This essay is meant to clarify this situation. National Catholic Bioethics Quarterly 10.2 (Summer 2010): 251–256. (shrink)