[labcomputer]

The data doesn't exactly support your argument though:

https://ourworldindata.org/grapher/births-by-age-of-mother

Just looking at raw number of births by age of mother:

* 15-19 peaked in 1989 and has decreased 35% since then

* 25-29 is higher than at any point in the 20th century

* 30-34 is higher than at any point in the 20th century

* 35-39 is higher than at any point in the 20th century

* 40-44 is higher than the 20th century except the 1960's

[usefulcat]

Bear in mind, those appear to be absolute numbers, not relative to world population.

[121789]

You are looking at the full world numbers, which isn’t really what’s being discussed in this thread. Try filtering for South Korea or the US

[labcomputer]

Sure thing, boss:

If we filter by US,

* 15-19 is down almost 80% (!!!) since the mid-century peak.

* 20-24 is down about 60% since the mid-century peak.

* 25-29 is about flat since mid-century

* 30-34 is higher than any time in the 20th century

* 35-39 is higher than any time in the 20th century

* 40-44 is higher than any time in the 20th century

In other words, the story is about the same as global.

Remember, I was responding to a comment that stated "Reduced teen pregnancies are not the driving factor in recent fertility rate declines at all."

If I was going to steel-man your argument, I would note that 20-24 is the cohort with the largest numerical reduction in the US... but then the argument still rests on splitting hairs that 20-24 are not technically teenagers, and teenage pregnancies "only" account for 40% the total reduction in fertility (while teenage mothers only accounted for 16% of births in 1970).

Of course, it's hard to square splitting those hairs with the definitive statement "not the driving factor [...] at all" (emphasis mine). In fact, the only way it makes sense is if you define "recent" to mean "since 2017", but measuring things like this over a period of less than a decade is silly anyway.

The data is also abundantly clear than older women are having more babies (not just a greater percentage, but actually more babies). In Japan women ages 35-44 had more babies in 2023 than any time since 1950. In Korea, women ages 30-44 had more babies than any time since 1980.

[interloxia]

Change in births, by age of mother, United States

Estimated number of births each year by the age of the mother. 1950-2023 relative change. https://ourworldindata.org/grapher/births-by-age-of-mother?s...

Birth rate by women's age group, United States https://ourworldindata.org/grapher/fertility-rate-by-age-gro...

[frm88]

The second graph is so interesting. Pulling the slider shows less births but an average increase in the mother's age (which in turn accounts for less births if you're looking at 35+ yo first time mothers you don't expect n more kids to follow for (among others biological/medical reasons)). It would be interesting to have a complementary chart on divorces just to have a look whether existential uncertainty plays a role in age decisions.