There are more higher IQ men because men have a higher variance in IQ, because men are risk-seekers, because of evolutionary biology. But that same high-variance that makes there be more really really stupid and really really smart men than women *also* makes men prone to stupid status-seeking like the academic track Greenspun describes. So its not just that there are more men than women intellectually capable of being a science professor, there are also more of them stupid enough to try.
In other words, Patri's pointing to a personality difference between men and women: Men care more about status. He's probably right, but there's a much simpler personality story that as far as I can tell has been totally neglected: Both the popular Jungian and the more academic Five Factor personality tests confirm the stereotype that men are more logical and women are more emotional. (The first class of test says that men are more "Thinking" and women are more "Feeling"; the second says that women are more "Agreeable." Take your pick.) The difference is about a half standard deviation in size. That's big; when you go out to the tails of the Thinking-Feeling personality distribution, men greatly outnumber women.
So what? Well, personality tests also confirm occupational stereotypes. Yes, librarians really are introverts. And yes, scientists are extremely Thinking - or, if you prefer, they're extremely Disagreeable. It's not a matter of IQ - Feeling people have virtually the same average IQ as Thinking people. It's a matter of cognitive style. No matter how smart you are, a scientific career won't appeal to you if you care more about how people feel than how things tick.
The big problem with other stories is that they don't explain variation in academic disciplines' gender ratios. My story does: In fields that appeal to Feeling people - like English literature and psychology - you'll see a much higher fraction of women than you do in math, physics, or econ.
Question for Discussion: Is my story more palatable than Summers'? How would academia and the world have reacted if he said "There are fewer women in science because women like science less"?