Heather Boushey's comment:
Sure, I'll comment ... I've run hundreds of regressions by now trying to sort out whether there is or is not a trend of declining women's employment *because of children.* I haven't found any real evidence that points to women being more likely to leave employment today, compared to 25 years ago or 5 years ago, because they have children at home.
What we know is that employment rates for men and women (moms and non-moms) declined after 2000, and while women's employment rates have almost recovered to their 2000 levels, men's have not.
We also know that women lost more jobs during the recession of 2001 than they had in the prior two recessions. They did not lose more jobs than men, but compared to women in prior recessions, the 2001 recession was hard on women workers. I tend to think of this as women moving closer to equality to men in their vulnerability to the business cycle. (Typically, in prior recessions, men have seen greater employment losses than women during recessions.)
When we isolate the effect of children on women's employment, there is no increase. Does this mean that women are not leaving the workforce? No, but it does mean that we cannot identify children as the cause.
There is some evidence that husband's income may be having a slightly -- very slightly -- larger downward pull on women's employment in recent years. But, that's not about motherhood.