Skeptic: Promoting Science and Critical Thinking

By comparison with all the other animals, humans have an odd sex life. Why? Sex is fun for us because human females have concealed ovulations and are constantly receptive. What evolutionary forces operated on our ancestors to make us sexually so different from other mammals? Why does the human male stand out as one of the few mammals to stay (often or usually) with the female he impregnates to help raise the children that he hopes he has sired? Why is the human penis relatively so large? Why does the human female, virtually alone among mammals, go through menopause? Why are humans one of the few species to have sex in private? Why do we have sex at any time in the fertility cycle, even when the female can’t be fertilized?

With wit and a wealth of fascinating examples Diamond explains how sexuality has been as crucial as large brains and upright posture in our evolutionary history.