[thrance]

Why did you just assume there are genes that predict "not wanting children"? It's happening uniformly all around the world, and is much better predicted by things like wealth and freedom than anything else: cultural reasons, not heredity.

[eudamoniac]

It is safe to assume pretty much any proclivity has some, however minor, genetic basis. Separated twin studies have shown enough similarities in basically every aspect of personality that it's a plausible bet.

All over the world, some groups are deciding not to have kids and some are. Globally declining fertility rate says nothing about genetic proclivity to want children unless fertility rate goes to zero.

[hn_throwaway_99]

I think you've misunderstood my point. To clarify, there was strong selection pressure in the past to "make sex desirable" (and obviously I'm oversimplifying a lot here, but the premise still holds) because that was enough to ensure that passing on your genes was the result a large percentage of the time.

Now, though, birth control has broken that connection between "having sex" and "making babies", so now "making sex desirable" no longer is enough of a trigger that results in passing on your genes. So, in that sense, the environment in which humans reproduce has changed drastically, in a short period of time. So now there should be strong selection pressure for people to have children beyond just making sex enjoyable. Whether that shows up in a stronger innate desire for children themselves or whatever I won't speculate on - I'm just making the point that widespread birth control is a huge change to humans' environment to which natural selection should act on, by definition. What I am not saying is that "not wanting children" currently is the result of some fundamental genetic difference between sub-populations.

[thrance]

I think my point still stands? For selective pressure to select anything, there has to be preexisting genes that predict how much someone wants kids. And again, cultural and material factors are so much more important than genetic ones on the matter, that I don't believe the latter has any quantifiable effect.