INTERESTING QUESTION WITH WHAT I BELIEVE IS A SIMPLE ANSWER
Um, it’s pretty interesting but (a) EAST Asians have succeeded in higher pedomorphism (retention of childhood features) resulting in the obvious lower sexual development in both males and females, and lower levels of testosterone. (b) east asians evolved out of an earlier branch of homo sapiens just as western europeans (‘whites’) did. and this branch has had less interference from outside genes due to the isolation of eastern asia by desert, mountain, and sea. This allows greater correction of genetic variations – at least prior to rice farming. (c) a lot of it has to do with the skin, which we have to admit, white people are at a disadvantage in compared to africans and east asians.
The optimum genetic position is to freeze maturity at the minimum point of fertility, and this appears to have been achieved in east asia.