It's certainly economically worse, sure, but on the other hand you might be optimizing for other things. I for one would like to know my grandkids, and if I hav

It's certainly economically worse, sure, but on the other hand you might be optimizing for other things. I for one would like to know my grandkids, and if I have my first kid at 40, and my kid has their first kid at 40, I'll have likely died of old age before my first grandkid reaches high school. Plus, I really like the idea of my kids being out of the house before my 60s. Factor those in with the studies about the relationship between the health of children and the age of the parents, and I'm willing to trade some potential income for those considerations (although that has limits, and having kids early can have quite substantial economic downsides, especially if you're a woman, and doubly especially if you end up out of the workforce entirely to raise them).