[_heimdall]

Your example would actually prove the negative here. Adopting a black kid into the white family did not change the kid's race.

Adoption only changes the kid's environment. How do you read that as an indicator that race was the differentiator?

Do you mean only race of the immediate family in the household, not race of the person taking the test? That seems like a stretch to say it's race based at that point, and also a pretty useless data point unless your recommendation is to somehow leverage that by adopting more kids into white families because your belief is that will make them score higher on an IQ test and that a higher IQ score is a meaningful enough metric to propose such a big intervention.