Sidney Callahan's column (June 19) gives a genetic continuity argument for the moral value of the early embryo. But her reasoning is flawed.
If her argument is logically extended, we would have to conclude that the sperm and the egg also have moral value. After all, the embryo is just a continuation of the genetics of the sperm and the egg.
In my view, the whole abortion dilemma is caused by human indolence. We seem unwilling to deal with a continuum when we see one. It is much easier to just classify things as either this or that. Nothing can be in between. In reality, however, prenatal development is a gradual process that has no definite "beginning."
The real value of human life gets cheaper and cheaper with each new billion that we pack on the planet. Surely, where there is ambiguity, we should err on the side of less births rather than more.
WILLIAM THWAITES, Associate Professor of Biology, San Diego State University