Get out the Nancy Hopkins smelling salts. This piece in the Boston Globe on women and science actually allows for common sense. Even a female academic makes some of it:

Princeton University president Shirley M. Tilghman, a molecular biologist, has spoken about how in her field, women are nearly half of new doctorate recipients, but only a quarter of faculty job applicants at top-tier universities.
”It does not take much imagination to recognize that the drop coincides with prime child-bearing years,” Tilghman said in a speech this year at Columbia University.

Another section, surveying women in science, is quite shocking:

Rud is a little unusual in having given birth to her first child in graduate school, but her soul-searching was echoed by more than two dozen other young female scientists in interviews with the Globe. Many of them are preoccupied with the question of whether to stay in academia at all, or whether to settle for less prestigious instructor positions.
These women, most of them studying in the booming field of life sciences, often describe working in laboratories where women are a robust minority, or even a majority, of graduate students and post-doctoral fellows. Few of them say they have experienced much discrimination. The primary barrier, they say, is the conflict between lab and family under the grueling demands of today’s academic culture.

And although the end of the piece talks about institutional blame–not enough daycare and family friendly policies, this undeniable truth gets out too:

Rud’s [Rud is a Harvard biology grad student and young mother] adviser, James A. DeCaprio, said few of the graduate students and postdocs he has trained, male or female, have gone on to academic research positions. Those who have made it tend to work about 70 hours a week. The rest end up choosing business or law school, the pharmaceutical industry, or teaching in less prestigious positions.
”If you work 80 hours a week, you will be twice as successful” than if you work 40 hours, he said, explaining that more hours translates directly into more experiments, and more discoveries. ”They move the science along faster than the competition.”