Inside Higher Ed just reviewed the new book Do Babies Matter? about gender and having babies in academia: This is from the review:
“A woman’s income incrementally decreases 1 percent for each child she has (men’s income is unaffected). Over many years and several children, the cumulative impact is significant; on average, women retire around the same age and for the same reason as men (the only career transition that isn’t ‘gendered’), but at a salary that is 29 percent lower, according to one data set.”
If this the topic that gets you going, note that they also reviewed the book Mothers in Academia.