The heated debate over research using material taken from human embryos continues, now with Philosophers insisting that this ethical concern isn't for scientists alone. Advocates of embryo use argue that at such early stages, the cells cannot be considered a human person. However, Robert George and Christopher Tollefsen argue to the contrary in their recently published book: "Embryo: A Defense of Human Life" (Doubleday). George and Tollefsen present scientific and philosophical principles to establish the human status of the embryo. They maintain that the status of human being commences at the moment of conception.
They write that our argument "was that nothing acts on the embryo in such a way as to 'produce a new character or new direction of growth.' This is a straightforward fact fully established by embryological science. Nothing in the developmental process (certainly no action of the mother) transforms the developing organism from one kind of entity (say a nonorganismic entity or a nonhuman organism) into another kind of entity (a human). Human development is the development of an entity that comes into existence as, and remains until death, a complete, self-integrating, determinate human organism—a human being." From here.
Their book begins with the story of Noah. He was rescued, along with other frozen embryos, from the Katrina disaster in 2005. It was a human life that was saved, George and Tollefsen point out, the same life that was later implanted in a womb and was born in January 2007.
George and Tollefsen hold that a human embryo is a living member of the human species from the earliest stage of development. Unless there is natural or human intervention, a human being in the embryonic stage will proceed to the fetal stage and progress to maturity. The embryo is not another type of animal organism, nor can it be dismissively regarded as a cluster of cells, but marks the material onset of a human life.
George and Tollefsen maintain that the process of becoming a mature human being can only be said to begin at conception.
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