I can think a couple of reasons.
https://www.npr.org/2021/07/26/1020810561/baby-bust-explaining-the-declining-u-s-birth-rate
I can think a couple of reasons.
https://www.npr.org/2021/07/26/1020810561/baby-bust-explaining-the-declining-u-s-birth-rate
Whenever experts can't figure something out I picture two people in a lab in labcoats stroking there chin and looking pensive and they have to stay and do that until they have an idea.