In his controversial new book, ‘A Billion Years of Sex Differences’, Professor Steve Stewart-Williams argues that how people differ can be scientifically grounded and that it shouldn’t be seen as sexist to say so. More than that, acknowledging sex differences, he says, can improve everyone’s lives H ere’s a fact that shouldn’t be controversial: men and women differ, on average, in their desires, interests, and behaviour . Here’s another: these differences are shaped not only by culture but also,