Mary Ann Mason (Berkeley School of Law, UC-Berkeley) in The Chronicle of Higher Education: How to Level the Playing Field for Women in Science. The article is largely about how to tackle the "baby penalty"; here are the key paragraphs:
Our most important finding is that family formation damages the academic careers of women but not of men. Having children is a career advantage for men; for women, it is a career killer. And women who do advance through the faculty ranks do so at a high personal price. They are far less likely to be married with children. We see more women than we used to in visible positions, like presidents of Ivy League colleges, but we also see many more women than men who are married with children working in the adjunct-faculty ranks, the "second tier," and one of the fastest-growing sectors of academe.
Our study also identified interventions that could help change that disheartening pattern. Some of these policies are now in place at some universities and are being promoted by some federal agencies. We are at a critical point, where the story could change dramatically: The "baby penalty" could be wiped out, or at least greatly ameliorated, by these four reforms: better child care (in many forms), effective dual-career policies, childbirth accommodations, and compliance with Title IX’s prohibition on pregnancy discrimination.