[exBarrelSpoiler]

Sounds like culture doesn't mean much when even the lands where the culture originated from willingly discard the cultural elements that lead to more children and larger families, even while preserving other elements.

Consider the case of the Islamic Republic of Iran:

https://fred.stlouisfed.org/series/SPDYNCBRTINIRN

https://www.dw.com/en/iran-birth-rate-decline/a-54371973

So much for white Americans and westerners.