It's probably about whether women are on a career track and, thus, what age they start having children. Poor women generally aren't on a career track. They finish school and start working a job that doesn't require school or much training. So they can (and do) have children pretty early. Rich women do usually go to college, but they meet a future husband there who is on a high-earning career track and are able to start a family relatively early because they don't have to help pay the bills.
What I'm saying, though, is that if you look at the fertility curve[1] you'll see that many middle class families could eliminate one earner and still have 2-3x the income as poor families that have more children. But people are choosing not to do that (well, secular people are choosing not to do that; intensely religious people often do exactly that).
What I'm saying, though, is that if you look at the fertility curve[1] you'll see that many middle class families could eliminate one earner and still have 2-3x the income as poor families that have more children. But people are choosing not to do that (well, secular people are choosing not to do that; intensely religious people often do exactly that).
That's what's interesting to me.
[1]: https://twitter.com/CSchmert/status/993934031174725632