[CWuestefeld]

I, too, was under the impression that this was pretty well accepted, at least as far as mathematical skills relating to the ability to handle spatial models.

Rephrasing your quotation, if you draw out the curves so that ability is on the X axis, and number of individuals having that ability is on the Y axis, then the curve for females will be taller and narrower than that for men.

That means that if you've got in mind a brilliant geometer, that person is more likely male than female. On the other hand, if you've got in mind an extremely bad geometer, that person is also more likely male than female.

Discussion of this that I've read have hypothesized that we've evolved this way because humans back a zillion years tended to have the males go out hunting while women took care of babies and domestic chores; and tracking and stalking prey demanded more of a person's spatial skills.