The way I understand it, the modern sentiment is to have children meaningfully, raising them being a project parents actively invest into. Contraception brought choice, choice brought up consideration and planning. This all opened the can of "what are we doing" and "why do we do it" and "how do we do it right", that tended to be ignored in previous eras (where having or not having children was not exactly a real choice).

And for little I know about raising children is that it's one hell of a job, that requires extensive knowledge, skill, and constant heavy investment, all being an unbreakable commitment for almost two decades. Messing anything up means another human suffers the consequences. In my mind, a would-be parents have to be really competent to be confident to be able to accept the responsibility, and even then screwups are a given. Skipping on any of that, even unintentionally or from inadequate skills, means a person out there will be left to figure out how to deal with the aftermath of their upbringing. The fact a lot of people skip on all of that and just do it is no excuse.

And thus, personally, I never felt like having children. Not seriously, not after thinking about it in any depth. I messed up two cats already, messing up a human is unnecessary.

IMHO, if a society really needs new people because can't figure out how to support old ones otherwise, it should invest into professional parenting and employ people who are genuinely enthusiastic about doing that work.