Men's brains are, on average, between 10 and 15 per cent larger than women's. In one recent study, neuroscientists compared the brains of 42 men and 58 women postmortem, and found that men's weighed an average of 1,378g (3lb), compared with 1,248g (2.75lb) for women. These size differences have been found repeatedly, but they emerge only when comparing large numbers of people, so some women's brains are larger than the average whereas some men's are smaller. These differences partly reflect the fact that men are generally bigger and taller than women, but they are not related to differences in intelligence. (http://www.theguardian.com/science/neurophilosophy/2013/oct/06/male-brain-versus-female-brain)