I'm aware, and using that specific example. The risk of all the bad things adding up, though, is still a small delta in absolute terms, for actual pregnancy, and the trends only show up across large enough sample sizes that still aren't that relevant to the lived experience of any given individual child.

And those same statistics tend to show bad outcomes for the under-25, and awful outcomes for the under-22, even at pregnancy. Basically my argument is that the magnitude of those effects is small, and swings the other way when you're talking about mothers too much younger than 30, too.

Throw in actual lifetime statistics around household income and wealth, divorce rates, etc., and it seems that looking to the entire childhood, the 30-year-old birth is close to ideal, with 5 years older being no worse than 5 years younger, and even 10 years older being no worse than 10 years younger. The individual variance is so much larger than the magnitude of the statistical trends, so broad population statistics don't matter that much for the individual. It's still a dice roll even if your stats are ideal.