Researchers of human behaviour have identified an "orgasm gap": Men usually orgasm during intercourse, whereas women often do not. This book addresses this mystery. The two leading explanations are either that women are “psychologically broken” - Freud’s theory – or badly designed – the “by-product theory.” However, there is a much more compelling third explanation. Evolutionary biology, anatomy, physiology, and direct sex research suggest women have evolved under their own selection pressures and orgasm is a fitness-increasing consequence of such selective factors. This is revealed in their patterns of orgasmic response, which are neither random nor inexplicable.

Key Features

• Synthesizes decades of peer-reviewed sex research in anatomy, biology, physiology, and behavior


• Engagingly written based on feedback from students, peers, and interested lay persons


• Makes sense of the “orgasm gap” between men and women


• Provides a wider context of human sexual dimorphism and mutual sexual selection


• Balances sex research and real-world research and practical applications.