The Evolution of Human Sexuality is a 1979 book about human sexuality by the anthropologist Donald Symons, in which the author discusses topics such as human sexual anatomy, ovulation, orgasm, homosexuality, sexual promiscuity, and rape, attempting to show how evolutionary concepts can be applied to humans. Symons argues that the female orgasm is not an adaptive trait and that women have the capacity for it only because orgasm is adaptive for men, and that differences between the sexual behavior of male and female homosexuals help to show underlying differences between male and female sexuality. In his view, homosexual men tend to be sexually promiscuous because of the tendency of men in general to desire sex with a large number of partners, a tendency that in heterosexual men is usually r