"If you were to predict the future on the basis of school achievement alone, the world would be a matriarchy," writes Pinker. Why, then, is it not? Second-wave feminism assumed that equal opportunities would lead to a "mathematically equal result" but, Pinker argues, women's brains are fundamentally different from men's, and the two sexes value achievement differently. This may have been heresy among 1970s feminists, but Pinker draws on a wealth of genetic evidence to back up her argument, which is mostly intelligent and meticulously researched. Yet, almost unavoidably, she makes generalisations. Why, Pinker asks, don't girls grow up to be more like their fathers than their mothers? I, for one, have done. What does that make me?

In the wrong hands, Susan Pinker's investigation into gender difference could become a very offensive weapon indeed. By arguing that evolution has primed women to make different choices from men - prioritising family over time-sucking careers, preferring work that involves people not things - the Canadian psychologist could thrust a told-you-so cattle-prod into the grasp of those who assert a woman's destiny is a gingham apron, not a business suit. Her book isn't about who has the "best" hormones, but why so many able, competitive women are forced into a system designed for men. Focusing on talented female students who later drop out of careers and "extreme" men who struggle at school with dyslexia or Asperger's syndrome yet excel in demanding jobs, she grapples with the very nature of prejudice, asking whether viewing women as victims of "discrimination" actually devalues their real desires. It's a dangerous game, but Pinker defends her point with good sense and, some might say, typically female empathy.