Teaching Evolution

A blog devoted to teaching evolution, both in our schools and in our communities.

Tuesday, May 17, 2005

Why do Women have Orgasms?

It's a subject I've studied closely through the years, of course, but from an evolutionary standpoint I had thought its origins were quite obvious. Why do women have orgasms? Because women who enjoy sex are more likely to have sex and therefore procreate and pass on their genes, right? Maybe not.

[I]n a new book, Dr. Elisabeth A. Lloyd, a philosopher of science and professor of biology at Indiana University, takes on 20 leading theories and finds them wanting. The female orgasm, she argues in the book, "The Case of the Female Orgasm: Bias in the Science of Evolution," has no evolutionary function at all.

Rather, Dr. Lloyd says the most convincing theory is one put forward in 1979 by Dr. Donald Symons, an anthropologist.

That theory holds that female orgasms are simply artifacts - a byproduct of the parallel development of male and female embryos in the first eight or nine weeks of life.

In that early period, the nerve and tissue pathways are laid down for various reflexes, including the orgasm, Dr. Lloyd said. As development progresses, male hormones saturate the embryo, and sexuality is defined.

In boys, the penis develops, along with the potential to have orgasms and ejaculate, while "females get the nerve pathways for orgasm by initially having the same body plan."

Nipples in men are similarly vestigial, Dr. Lloyd pointed out.

While nipples in woman serve a purpose, male nipples appear to be simply left over from the initial stage of embryonic development.

This is just the type of story to get schoolchildren interested in evolution.


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