Let me begin by clearly stating that if you PREJUDGE someone on the basis of ethnicity, then that's prejudiced and wrong. For example, if you believe that Latinos are dumb, and you prevent someone named Fernandez from entering a gifted program (or getting hired to a job they're qualified for, etc.), then that's immoral and also not supported by any science. Although there MAY be some differences in mean IQ between ethnic groups, as one scientist said, the world's greatest mathematician might come out of the poorest slums of India. According to some, Neanderthal DNA that is found in Europeans and Asians MAY give them a statistical advantage over Africans who do not carry those genes, but this is only a statistical advantage, which you cannot use to make a priori judgements about an individual. (In other words, any facts about ethnicity and IQ statistics are interesting to anthropologists but not managers or school administrators.)
However, once you eliminate the prejudices, are there any genetic features that may make one group have a slightly lower probability of generating geniuses than another? I've read scholarly papers that showed, for instance, that Africans have a slightly lower mean IQ than Europeans, who have a slightly lower mean than Asians. (Note that the gap between whites and blacks in America is much smaller because of a lot of mixing.) Mind you, this doesn't account for the variance, where we find that the groups have vastly more overlap than they do difference. It also doesn't account for other adaptations, like how Africans have been shown to have superior social ability, and although it doesn't show up in IQ, it does show up on other measurements that any decent intelligence test should include. We have to keep in mind that we are a single species, and although there are some geographically separated groups, each group is very well adapted to their environments.
Then there are social factors. Parents that aggressively educate their young children before preschool will give those kids an advantage, rightfully pushing many of them into gifted status, regardless of what their IQ might have measured as if other factors had been equal. Regardless of genetics, the human brain is very flexible, and early education can have a profound effect on later intelligence. So your black and hispanic families who whip their kids into doing their homework and learn their ABCs early will outperform kids of lazy white parents, and they should be judged on performance, not probabilities.
It'a also interesting to see how measured intelligence is biased by socioeconomic status. It doesn't matter what color you are -- if you're poor, you're very likely to score lower on intelligence tests. Now, there is surely some interaction between socioeconomic status and gene transfer, and that's interesting once again to anthropologists. But what it really tells us is that people with lower incomes are disadvantaged by more limited educational opportunities (and/or educational aggression from parents), and to improve our society, we need to improve education among the poor. And education is the great equalizer.