Via PZ Myers' blog, I see that DNA discoverer James Watson stated that Africans were less intelligent than other races (and Watson has a history of controverial statements). Myers disagrees with Watson but doesn't think he should be punished.
Two years ago, Larry Summers suggested without stating he believed it that genetic factors might account for why women are under-represented at top levels in academia. His statement was a big reason for his having to leave Harvard, and I remember Myers saying he should be fired (can't find a link for it though).
The idea supporting Summers' statement wasn't that men are smarter than women on average, but that men's fewer X chromosones mean less moderation of unusual genes, so more diversity in genetic expression means a wider distribution of intelligence, with more stupid men and more smart men compared to women.
It's not an impossible idea, but there are so many confounding cultural factors that looking at under-representation in the academia is extremely weak support for it.
The person who should have tried the idea is Watson, though. Summers had to hypothesize about increased genetic diversity for men in intellectual traits, but we already know that there's a significant difference in the level of genetic diversity between Africans and non-Africans. The more diverse group could be expected to have a wider distribution of genetically based intelligence traits, and the fatter tail at the high end of the distribution curve would mean that group would have more high performers.
The kicker to this is that it's the Africans who are more genetically diverse than non-Africans, yet we don't see a wave of academics leaving Africa and overwhelming their slower, non-African counterparts.
I don't consider all this to be a refutation of the idea that ethnicity or gender can have some effect on intellectual performance. It might, and maybe Africans do have some intellectual advantage at the high end for all I know. I do think though that it's a refutation of the idea that genetic differences are at all large at any level, and instead, other factors are far more important.
And I think foolish speculation about this stuff by two academics who, let's face it, have a disadvantageous genetic background, shouldn't get them fired.