How different are the sexes? Is gender uniquely human? Where does gender identity originate? Drawing on decades of observing our closest living relatives, chimpanzees and bonobos, world-renowned primatologist Frans de Waal explores what we know of biological sex differences and of the role of culture and socialization.

From maternal and paternal behaviour to sexual orientation, gender identity and the limitations of the gender binary, de Waal analyses our shared evolutionary history with the apes, considering what is similar and what sets us apart. Male and female networking groups, sexual signals, the existence of gender non-conforming individuals and maternal bonds are observed in primate societies, but humans stand apart in the development of nuclear families, the prevalence of sexual violence and joint parental care.

With expert insight and engaging storytelling, de Waal not only sets right gendered biases in the scientific community, and delivers a fresh and thought-provoking understanding of the behavioural norms and the many remarkable potentials of the human species.