Scientists and Motherhood » American Scientist

As the husband of another professor and a parent of twins, I agree that the demands of parenthood are a compelling reason that more women than men leave high-demand career tracks. In our culture, women still do more parenting than men, so the burden falls asymmetrically on them. I would also argue that, compared to men, women define their self-worth less through their careers and more through their children and family life, leading to different priorities. But in the few fields that are highly math intensive (such as physics, mathematics or some areas of computer science) I doubt one can exclude the possibility that a gender asymmetry in ability plays a role. Given that ability is approximately normally distributed, a small asymmetry with no practical effect in the middle of the distribution can have significant effects on the gender ratio of the small number of outliers that are suited to research in quantitative subjects. Williams and Ceci should also consider mechanical engineering, which probably loads on spatial reasoning ability and which has one of the lowest female representations. Spatial reasoning ability is very gender asymmetric, according to the data I have seen.