University of Virginia economist Amalia Miller has made a small stir recently with her finding that women who delay having kids past their twenties make more money. The headline finding was that a year of delayed fertility leads to
• a 10% increase in career earnings,
• a 5% increase in career work experience, and
• a 3% increase in career average wage rate.
This finding has been troubling because it runs up against the fact that women’s fertility falls off significantly after their twenties.
SO, if a women wants to have kids, she should start having them before 30; if she wants to make money, she should have them after 30. Or not at all.
On the face of it, this is not an unreasonable conclusion. Kids cost money, both in direct costs and in the opportunities to make money that parents, especially moms, forego. You might see this as a tragic choice, or a choice between two different values.
I do see one problem with Miller’s account that I find troubling, though. She lumps together college graduates with graduate degree holders. Yet women pursuing graduate degrees would be more likely to be in school still in their mid-twenties, and would likely have higher earnings no matter what their fertility choices. Since the biggest returns come to managerial and professional women, this is the group in which the effect of delayed fertility for schooling and earnings affected by schooling should be greatest.
In other words, women with graduate and, especially, professional degrees are likely to make more in the long run anyway, regardless of whether they have kids or not. As a group, they are more likely to have kids later than other women. They skew the whole pool. It could be that they make more because they delayed starting motherhood. More likely, though, they make more because they trained for more lucrative professions. One side effect of their training was that they are less likely to have kids in their twenties.
Now women with graduate and professional degrees often do make a choice for career over children, sometimes by just waiting too long to start on kids. As I have lamented elsewhere, most women with Ph. D.s do not have any children. Some do it for the money, some for the career itself. I think that for most of the high-earning/low-momming women, though, they did not so much make a choice as make a “creeping non-choice,” and then live with the results. The evidence convinces me that most women do not pick their careers primarily to maximize lifetime earnings. People who do that are more likely to be men. Or economists.