The fertility rate has relatively plummeted pretty much anywhere with a socialized retirement system.
Why would you go through the trouble of kids when you can just mostly offload the time and cost of that on someone else then tax those kids when they're grown for your own retirement and get about the same size slice as the person that actually raised them?
Most Americans don't have the mathematical rigor to understand a rent vs. buy calculator, but I love the idea that every American without kids understands how to calculate the present value of a deferred annuity against the cost of raising a kid and have made the multi-decade commitment to forgo family life simply as a result of that calculation and knowing that they will come out ahead in the end.
And yet in times century ago every simple farmer understood it. The principle is simple, watching your childless neighbors relatively suffer is not hard to understand.
That calculus totally changes if the childless neighbor can just send armed men to collect the neighbor child's income and redistribute it to themselves.
Doubt this is the explanation. Fertility has declined because easy access to contraception has completely altered the trade-off of having kids. Before you could essentially be celibate and not have kids or you could be sexually active and eventually end up with kids. People want to fuck more than they don't want kids.
Contraception (especially the pill), has eliminated this trade-off. Now people can have their cake and eat it too.
On average I'm not sure it's as 'relatively' deep. Definitely merits further study. Most the places I can think of without a social security system had drops but not the inverted pyramids we're seeing in the west.
Ah yes. In the '90s and early '00s the decline in fertility was laid at the feet of feminism and reproductive choice. And now that Roe v Wade is gone it's because of Social Security. After Social Security is destroyed I wonder what will be blamed next? Income taxes or loss of the gold standard, probably.
IIRC studies on joy of children, there is pretty marginal gains in satisfaction with having children beyond one, except a weird bimodal blip somewhere beyond 3 that trends with a small segment of society that really loves pumping out kids.
Why would you go through the trouble of kids when you can just mostly offload the time and cost of that on someone else then tax those kids when they're grown for your own retirement and get about the same size slice as the person that actually raised them?