Blog/2025-02-14/Fertility Rate
Everyone writes about the fertility rate crisis at some point. There are many theories as to why it occurs: chemicals, gender divides, doomer culture, and so on. My pet theory has been opportunity cost. A little while ago, my friend Diane wrote about this same thing. Now, the first thing to note is that the availability of contraceptives and abortion have transformed us from the 8 children per mother world into a 2 children per mother world. Even fertility oriented cultures like Ultra-Orthodox Jewish communities use contraceptives to manage pregnancy.
Now, I won't rehash any of the arguments. But I just wanted to put a little visualization of the difference between high prosperity environments and low prosperity environments with some simple assumptions:
- The joy inherent to being a parent is prosperity-independent
- Societal utility is prosperity-dependent
- Late gestation and the early stages of parenthood remove the ability to access societal utility
Where 'societal utility' is just what you get from being in society: your career, your social life, travel, all that. It falls out naturally from that that if you increase societal prosperity, you can access far more societal utility. People respond quite quickly to increased costs or increased buying power, even if only instinctually.
So then it's a matter of the parameters. You can raise child utility really high and they'll have kids simply because total utility is way higher. You can raise societal utility really high and they'll abandon kids just because total utility is way higher that way.
This doesn't mean that this is precisely the explanation for how things are or that this specific model with those specific sigmoid parameters are exactly how people behave, but that even bare reasonable assumptions create
