Evolution by sexual selection is an idea that goes back to Charles Darwin. He had little doubt that it explained much about human beings, and modern biologists generally agree. One of them has even put a figure on it, concluding that some 54.8% of selection in human beings is effectively caused by reproduction of the sexiest rather than survival of the fittest.

Some years ago, the evolutionary psychologist Geoffrey Miller in his book "The Mating Mind" explored the notion that...