I was literally told as a kid that we were heading to overpopulation and that having kids would be immoral. The Chinese committed a genocide against girl infants with that as a justification.
I'm not saying that's something that can't happen, I'm saying it can't last for long.
The "immoral to have kids" crowd still exists e.g in Europe but their options are to either change their mind or to be gradually overrun by people who think otherwise.
