I have no doubt that there's a genetic difference with respect to one's ability to score higher or lower on an IQ test. Whether there's a difference among "races" depends on how you define a "race."  And, of course, there really are not too many people that are 100% genetically of one "race" or another. That being the case, what percentage would be the tipping point in terms of IQ scores? And I'd wager there are significant variations withIN  a given "race," which also have to be explained before any conclusion can be drawn about "racial" differences in general. Fascinating subject, that's unfortunately is strewn with minefields no matter how one approaches it!