Here's an interesting article by Peter Lawrence of the Medical Research Council Laboratory of Molecular Biology, Cambridge, about the gender gap in scientific fields:
Lawrence cites Simon Baron-Cohen's research into gender differences, and describes some average characteristics of the female brain and the male brain, which he believes are strongly dependent on biology and genetics:
Apparently, Science considered this article for several months but declined to publish it, causing a minor "eruption" over the issue in the scientific community (or so the Daily Telegraph says).
I am not sure of the research into all this, so obviously not sure how correct all the assumptions are. But I am persuaded not only by this article but by life experience to think that women and men-while equally valuable and intelligent-are different, think differently, and value different kinds of human relationships.
Maybe this explains some of the overwhelmingly female presence in nursing and elementary education. Often we see this explained as cultural bias, but I wonder how much might simply be due to "the female brain"? That is, men may still rule out nursing and elementary education due to some perceived cultural bias, but women are probably often attracted to nursing and elementary education because of something implicit in those fields.