Although I am not a chemist, Valerie Kuch, of the American Chemical Society is presenting some interesting data on women in chemistry. The argument usually proffered as to the low retention of female faculty is that we have a leaky pipeline. The question is why is the pipeline leaky. Why do women, who account for ~ 30% of BS degrees in my field, account for only ~ 10-20% of Ph.D.'s, and ~ 10% of faculty? It is a difficult question. Usually the answer offered is that women experience the demands of childrearing more heavily than men. But in Dr. Kuch's studies, she found that the loss of women from the tenure track pipeline occurs even for women who do not have children. It is clear that children alone cannot account for this effect.
I think some of the problem comes from having an uncomfortable environment. I have heard stories of women who receive a substantially higher teaching load and service requirements than their male colleagues. Unfortunately, these components are much less important in the tenure package at most research I universities. Effectively, this behavior stacks the deck against female assistant professors.
To some extent, it is understandable. There are many committees that feel they would benefit by having a female faculty member. If you are the only one in your department, it is logical that you might get recommended for more than your share. Also, there appears to be a perception that women are better teachers. Honestly, I'm not sure of this. Many of my best teachers in grad school were Men, but given the stereotype there is a push to assign extra teaching duties to women faculty. The key is for women to learn to say no.
Saying no is harder than it sounds. In many cases, you may really want to sit on that committee or teach that extra class, but the time required will take away from your research program. Unfortunately, at research I universities, it is all about the research. Women must learn to evaluate their opportunities and make choices, both in the classroom and at home. Of course I want to be successful, but for me success includes a happy family life and opportunities to pursue my academic interests. It is unfortunate that many of the scholarly activities that women enjoy (teaching, outreach, service) are not highly valued in the tenure package. This is something that women must work to change. I will do my part, but change really needs to come from women at higher ranks (i.e., full professor). Until then, I will learn to evaluate my options and say no to those not likely to advance my career.