> The overwhelmingly more likely (but incompatible with field political dogma) explanation is that income is most strongly mediated by intelligence, which is mostly genetically heritable. This is why people tend to have similar incomes to their parents.

This can't explain the whole effect, because:

- The effect of parental income on later income remains even after controlling with standardized test scores.

- Further, parental income seems to increase child IQ a little bit, even after controlling for parental IQ scores.