Fallingblood is correct. This controversy started back in the 1960s, when the US was struggling with its apartheid problem. The white supremacist side used the "scientific" standard of IQ testing to fight school desegregation, among other things. It really heated up in the 1970s. See, for example,
Academic Ignorance and Black Intelligence, an
Atlantic Monthly article published in 1972, on exactly the same issue. After all these years, we are still debating this issue, and racism is still going strong in America (despite the Supreme Court having declared it dead).
To be crystal clear, the rebuttal of the "genetic argument" is that the claim is based solely on a statistical pattern grounded in IQ testing. No racially-linked genes or DNA sequences have been isolated that are shown to explain the effect. The reality of that pattern is not under dispute--African Americans usually do more poorly on IQ tests. The rebuttal focuses on the assumptions underlying IQ testing--that it actually measures "intelligence"--the culturally-biased conditions under which the tests are given, and cultural differences in behavior. What Bill Labov did in his famous sociolinguistic study of language testing (which tended to show a smaller vocabulary in African American children) was that something as simple as the race of the person administering the test could produce radically different results. There is also evidence that the test score gap can be radically altered by changing environmental factors--exactly what you wouldn't expect if the IQ testing differences were genetic (see
The Black-White Test Score Gap).
It should be clear after half a century of debate that people won't stop waving the IQ flag to fan the flames of racism. As Noam Chomsky once asked, how would it change public policies even if there were some kind of genetic difference in intelligence between the races? The answer is that it would have no effect at all. It would not justify apartheid. It would not lead to different, more rational policies. The only reason it even gets debated is the subtext of racial animosities.