“Evolutionary scientists have never had difficulty explaining the male orgasm, closely tied as it is to reproduction. But the Darwinian logic behind the female orgasm has remained elusive. Women can have sexual intercourse and even become pregnant – doing their part for the perpetuation of the species – without experiencing orgasm. So what is its evolutionary purpose?

Over the last four decades, scientists have come up with a variety of theories, arguing, for example, that orgasm encourages women to have sex and, therefore, reproduce or that it leads women to favor stronger and healthier men, maximizing their offspring’s chances of survival.

But in 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.

…Dr. Lloyd said scientists had insisted on finding an evolutionary function for female orgasm in humans either because they were invested in believing that women’s sexuality must exactly parallel that of men or because they were convinced that all traits had to be “adaptations,” that is, serve an evolutionary function.

Theories of female orgasm are significant, she added, because “men’s expectations about women’s normal sexuality, about how women should perform, are built around these notions.” …Central to her thesis is the fact that women do not routinely have orgasms during sexual intercourse.” (New York Times )