well, you know, women are in traditionally in fields with a lower market value, such as teaching and English, while the higher paying fields, such as Business, and Engineering overflow with males - blah blah blah.[Psych should be about 50% female - I'll have to check the Chronicle on the male/female breakdown.]
p.s. "unkown" above is wendy
I suspected that might be part of it. Although it does lead to the question of which came first, the low wage of the female predominance...?