[pashsdk27]

Yes, maybe civilizations of social biological species that have a relativity low replication rate like us may find contentment with colonizing only a few close star systems. Create a few dense population clusters like our current cities on select planets and space platforms and leave the rest to 'nature'. We already have a declining population growth rate of 1.1 as more people are opting out of starting a family and children due to technological advances and better global socioeconomic conditions. And maybe our current power fantasies of galactic colonization may seem trivial and 'ignorant' to our future generations. One could also call this a great filter. The possibilities are endless and allows one to enjoy it as a bunch of inconsequential thought experiments. Actual problems that require solutions are usually not fun to think about.......

[ALittleLight]

Low fertility among women is not due to desire but to demands of modern society [1]. Women typically desire 2-3 children each. In modern society they can't have them because of low marriage rates and increased employment among women.

1 - https://ifstudies.org/blog/how-many-kids-do-women-want

[sdenton4]

Interesting collection of stats, though I don't think the author's conclusions are the only possible interpretation. It's clear that the family size intentions really have been falling since the 60s, and that actual fertility is a fraction of that, which is unsurprising. The bigger sorry here, I think, is that the intended family size drops from 3.4 kids to 2.0. Possibly what's happening is that 'high producers' now make four kids instead of ten, bringing down the overall averages. Basically, it would be nice to see how the distributions of kids per woman change over the decades... I expect something at least bimodal, with a shrinking tail.

(Ed: fixed a couple stats, removed a bad statement about quotients. :P )

[ALittleLight]

One problem with the data is that it's hard to know to what extent modern life changes how many kids you want. Meaning: if a woman knows she has to have a full time job, she may only want, or believe she can afford, two or three children. Conversely, I suppose a woman in agricultural setting might want 7-10 children knowing they could help on the farm. It's probably impossible to know what people would want "unconstrained" by reality, and maybe not even meaningful.

Two things I think are true though. First, women have fewer children than they want, even if what they want is declining over time. Second, women who don't want children, or who want children below replacement, won't ever become the majority of the population - at least not for any significant amount of time. Such women will be replaced by women who, genetically or memetically, want more children.

[sdenton4]

"Such women will be replaced by women who, genetically or memetically, want more children."

That's not necessarily true. The rural population has shrunk significantly, even as rural family sizes tend to be bigger. The kids largely move to cities (following the gigantic trend towards urbanisation, and in responses to economic realities), and then proceed to have fewer kids in the urban context.

If there's a context with high birthrates, you've got to account for replacement rate within the context: there's a tendency for the kids to find their way to other contexts and thus revert to the mean. Insane "quiverfull" people have lots of kids, but it's not clear to me that they manage to keep up the crazy across generations.

[ethbr0]

How often has low fertily held true in virgin-frontier, resource-rich scenarios though?

[XorNot]

We've never had one where reliable birth control was available, so there is no data.