> I'm just going to throw this out here: only about 10% of nurses are male.
I think this is partly caused by the fact that men and women have a different natural tendency to enjoy nursing. (Honest question – is this belief politically incorrect?) If you completely filter out cultural effects, the tendency to incline to a specific profession will differ between genders, at least very slightly (that's just statistics). Of course, the very hard question is how big is this difference.