Something being "incredibly obvious" is not scientific evidence. First thing, there are huge genetic differences in non-mental traits, like height for example.

Something being "incredibly obvious" is not scientific evidence. First thing, there are huge genetic differences in non-mental traits, like height for example. No one doubts that. And many people use those to infer the same is true of mental qualities, but that would need to be proven separately. Heritability studies show that IQ is in fact significantly heritable. But these do not prove what non-scientists often assume. Heritability is the percentage of variability due to genetic differences, but it is always relative to an environment. Genes are meaningless without environments. For example, if we as a cultural thing feed shorthair cats different diets than longhair cats, and the diets affect their weight, then genetics would explain much of that variability. Cat weight would be heritable, strictly speaking, but in a different environment - all cats get the same food - it would not be. Various sources of evidence show that IQ is heritable in humans, but depends heavily on the environment. For example, adopted black children have higher IQs when raised by white parents, most of the difference between black and white kids goes away in that case. Is that the final answer? We honestly don't know. To really study it, we'd need to do unethical things - raise people in controlled experiments - which we simply won't do. But we do know that cultural effects are very large, and they might mask genetic effects. In practice, though, heritability still holds. People are born with genetics and those genetics are correlated to certain environments, and reactions from those environments. So even if in some theoretical way we are "born with equal mental potential", given the world as it is, that simply isn't true. But it could change.