A lot of white Americans have adopted Asian babies. Some of these American families also have biological children. I see the possibility of a study that could shed a great deal of insight on this question, if any researcher would dare to do it. How do these adopted Asians perform academically compared to their white siblings?
That would not be a “controlled” study. Why?
Because of differing societal norms and memes for different ethnic groups. It might have been more of a controlled study had it been done in 1920.
Today’s societal norms teach that Asian kids excel which create. Whereas they teach that white kids are the decendents of savage slave owners and oppressors of the global population. (They have no common role models, heros to look up to and are villianized in mainstream media and academia.)
The end result is what’s called a self-fulfilling prophesy.
There have been such studies and they show that the adopted kids intellectually are much closer to their genetic parents than their adopted ones.