Dr Michael Mosley and Professor Alice Roberts investigate if male and female brains really are wired differently. New research suggests that the connections in men and women's brains follow different patterns, patterns which may explain typical forms of male and female behaviour. But are these patterns innate, or are they shaped by the world around us? Using a team of human lab rats and a troop of barbary monkeys, Michael and Alice test the science and challenge old stereotypes. They ask whether this new scientific research will benefit both men and women - or whether it could drive the sexes even further apart.