[thriftwy]

Evolution at the moment tremendously favors these who can bear children late in their lives. That implies being in full health longer as well.

That would surely manifest in a few generations, sans some big civilization collapse. Or artificial uterus, for sure.

[WalterBright]

Does it? The odds of birth defects and disorders increase steadily with age.

[thriftwy]

Those for whom these odds increase faster are at huge disadvantage whereas those for whom it increases slower are at huge advantage. As you can imagine it is variative.

Of course I should have said "those who can bear healthy children late in their lives".