A new study by the University of Edinburgh suggests that although mean 'intelligence'* is the same for women and men, there are many more men in both the top and bottom 2 percent (reported in the Times, here). The study tests brothers and sisters, in a way that's meant to eliminate the differences in family background that may influence results - but even within the same family, the way boys are taught and encouraged may be different to the way girls are, so what does that prove? What I find even more questionable is the idea that this is somehow an evolutionary trait - surely the fact that men fall into both the top and bottom areas shows that there hasn't necessarily been an evolutionary advantage for more 'intelligent' men? The Times reports Joan Harvey of Newcastle University as saying: “Men and boys are socialised into higher levels of achievement.”
* lengthy complaint about the impossibility of defining, identifying and testing intelligence in any meaningful way deleted, see Stephen Jay Gould's The mismeasure of man for more.