I heard a recruitment bloke spouting off about why male applicants do better at the mechanical knowledge tests than females.
He reckoned it was because the tests were designed by a man.
I recently saw a programme on BBC World about genetics, discussing just this issue.
They believe the gene responsible is the same as the one which causes autism. The price males pay for having greater mechanical skills is that 9 out of 10 autistic children is a boy.
Any further developments?