The Sexual Evolution: How 500 million years of sex, gender and mating shape modern relationships

'Marvellous fun' THE TIMES

'Glorious . . . guides the reader with authority and humour ' LUCY COOKE

We find ourselves in a time of great social upheaval. People are testing the boundaries of just about everything related to sex and gender. Biological sex, long thought to be a simple binary, is now being understood as a spectrum. Gender is being uncoupled from sex and expanded to an astounding range of diversity. The traditional categories of sexual attraction are being supplanted by more creative labels. Where is this shift coming from? The answer may surprise you. Diverse sexual behaviour is not a new development, or even a human one. It didn't emerge from recent progressive culture, it's the product of billions of years of experimentation throughout the animal kingdom.

Evolutionary biologist Nathan H.