That's true currently, but only because of very long cycles, I think: there are still plenty of male professors in the humanities today who got their PhDs in the 1960s and 70s, when all of academia was male-dominated. But men make up around a 40%-and-declining proportion of new non-science/eng PhDs, which is actually not much better than the women in science/eng numbers (women make up about a 35%-and-rising proportion of new science/eng PhDs). In some fields it's closer to 25%, since that 40% of men getting humanities PhDs are strongly clustered in a handful of fields (like philosophy, which is still male-dominated). I think things are going to look quite interesting in 20-30 years once the current crop of older profs retires.