"For more than three decades evolutionary psychologists have advanced a simple theory of human sexuality: because men invest less reproductive effort in sperm than women do in eggs, men's and women's brains have been shaped differently by evolution. As a result, men are eager for sex whereas women are relatively choosy. But a steady stream of recent evidence suggests this paradigm could be in need of a makeover. 'The science is now getting to a point where there is good data to question some of the assumptions of evolutionary psychology,' says social psychologist Wendy Wood of the University of Southern California."