It is only when he ventures onto the subject of human sexuality that Ridley s argument becomes visibly weak. He bases his argument that women are less interested in sex qua sex in part on the reported lack of lesbian promiscuity, ignoring the strong societal pressure against women initiating or enjoying sex. He mentions some of Hrdy s primate work, but discounts it as being relevant only to primates. He discusses recent evidence for female human promiscuity. Sperm would not evolve to compete with other sperm unless women often had several sexual partners at the same time.
Women are more likely to orgasm at the appropriate time with extramarital partners.
One-fifth of children, on average, aren t related to their ostensible fathers. Male polygamous voles have better spatial conception than female voles of the same species. From this single unconvincing example, using a species far removed from humans, he concludes that the observed differences between men and women must be genetic. When a family in a car gets lost, the woman wants to stop and ask the way, while the man persists in trying to find his way by map or landmarks. So pervasive is this clich that there must be some truth in it.