Sagot :
The question as to when the physical material dimension of a human being begins is strictly a scientific question, and fundamentally should be answered by human embryologists�not by philosophers, bioethicists, theologians, politicians, x-ray technicians, movie stars, or obstetricians and gynecologists. The question as to when a human person begins is a philosophical question. Current discussions on abortion, human embryo research (including cloning, stem cell research, and the formation of mixed-species chimeras), and the use of abortifacients involve specific claims as to when the life of every human being begins. If the "science" used to ground these various discussions is incorrect, then any conclusions will be rendered groundless and invalid. The purpose of this article is to focus primarily on a sampling of the "scientific" myths, and on the objective scientific facts that ought to ground these discussions. At least it will clarify what the actual international consensus of human embryologists is with regard to this relatively simple scientific question. In the final section, I will also address some "scientific" myths that have caused much confusion within the philosophical discussions on "personhood."
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