Throw a Foxtrot

Plenty of answers already.

I’d like to point out that it’s not medicine alone, but empathy that changes natural selection. We have evidence of our ancestors caring for members of their tribe that would have been unable to survive otherwise.

But while in some edge cases (some diseases) you could make an argument that it’s bad for future humanity for some reason, it’s overall good, because it enables a larger population. And a larger population has a better chance of mutating to fit changing environments. Or to phrase it differently: diversification comes first, selection can wait.

Actually education is probably the largest selection factor. Educated people have less children than less educated people. Sometimes massively so. This is not necessarily linked with intelligence, it correlates more with socio economic factors.