Is there a consensus among the experts on this? Well, one place you might look is the American Psychological Association's 1995 report on "Intelligence: Knowns And Unknowns," written in response to the Bell Curve. The Wiki page is here. Money quote:
"There was a long-standing 15 point or 1 SD difference between the intelligence test scores of African Americans and White Americans, though it might have narrowed slightly in recent years. The difference was largest on those tests, verbal or non-verbal, that best represented the general intelligence factor (g). Controlled studies of the way the tests were formulated and administered had shown that this did not contribute substantially to the difference. Attempts to devise tests that would minimize disadvantages of this kind had been unsuccessful. The scores predicted future achievement equally well for blacks and whites.
The cause of that differential is not known; it is apparently not due to any simple form of bias in the content or administration of the tests themselves. The Flynn effect shows that environmental factors can produce differences of at least this magnitude, but that effect is mysterious in its own right. Several culturally based explanations of the Black/ White IQ differential have been proposed; some are plausible, but so far none has been conclusively supported. There is even less empirical support for a genetic interpretation. In short, no adequate explanation of the differential between the IQ means of Blacks and Whites is presently available."
So the consensus is: we don't really know why this gap exists but it does and it's persistent. It's not the only group difference:
Males do better on visual-spatial tasks, with a particularly large difference on mental rotation (nearly 1 SD), which is significant for their generally better performance in tasks that involve aiming and throwing. Males also do relatively better on on tests of proportional and mechanical reasoning as well as on mathematics. Females do better on verbal tests and some memory tests. They do relatively better in tests of literature, English composition, Spanish, reading, and spelling. More males have dyslexia and stuttering.
Here, the role of testosterone is crucial. And I got into trouble with writing the obvious truth that men and women are biologically different as well. Look: I'm not trying to stir stuff up for its own sake. But I believe conservatism is about facing reality. And that means we should have unfettered research into reality. Especially when we don't know why an obvious social fact exists. A reader writes:
I'd like to point out that the left's position on this issue is not really comparable with the right's position on climate change. There are real problems with the genetic interpretation of the very real race difference in IQ scores. There are also real problems with 100% environmental interpretation of the very real race difference in IQ scores. The only indefensible position to have at this moment in time is that there aren't real differences in IQ scores.