Anthropology books seem most interesting when they talk about sex, and this one’s no exception.
Sex at Dawn is dedicated to debunking myths that our species is, at heart, a monogamous one with hypersexual males and reluctant females. Tons of fun stuff about primates and hunter/gatherer cultures suggest that the human animal likes lots of sex with lots of partners.
It does seem amazing that the idea that there’s anything natural about the nuclear family has gotten any traction at all in the face of our desires and behavior.
Also, gorillas have a one-inch penis.