In nature, there are two reproduction techniques used for survival: r-type and K-type

R-type is "rapid" and it's where the mother will have multitudes of children. Oysters and octopodes areed dan excellent example.

K-type is very selective, because the offspring require immense quantities of resources. Elephants and giraffes are good examples.

Now, apply this same idea to Africans and Japanese, respectively. It is verboten to express this idea in the scientific literature