China too. They eat a LOT of soy and there is no sign they are having trouble making kids.
Perhaps they CAN make kids, but they aren’t.
Fertility rate for China is 1.77, considerably lower than the US and right in there with a number of the demographically suiciding European countries.
Japan (1.22) and South Korea (1.29) are even lower.
China has a lot of people, but few of them are kids.