JD Vance and Elon Musk are mostly really upset that teen pregnancy rates have fallen tremendously in the last 30 years in the US.
Over half the decline in the US fertility rate is from the decline in teen pregnancy.
A third of the "missing births" would have been unplanned and a majority would be to low income women.
And for many college educated women, they are delaying the children they would have had in earlier generations, not forgoing children altogether. They want basically the same number of children as previous generations, they just are having them in their early 30s instead of their late 20s.