A Distinct Human Organism

National Public Radio, November 22, 2005.

The key question in the debate over stem cell research that involves the destruction of human embryos is: When does the life of a human being begin? To answer this question is to decide whether human embryos are, in fact, human beings and, as such, possessors of inherent human dignity.

Where do we go to find the answer? Not, in my opinion, to the Bible, Talmud or other religious writings, even if we regard these texts as sources of moral wisdom and even divine revelation. Nor should we be satisfied to consult our “moral intuitions.”

Rather, the answer is to be found in the works of modern human embryology and developmental biology. In these texts, we find little or nothing in the way of scientific uncertainty: “…human development begins at fertilization…” write embryologists Keith Moore and T.V. N. Persaud in The Developing Human (7th edition, 2003), the most widely used textbook on human embryology….