Gene Expression has 10 questions for Jim Crow (and answers). Here’s Crow, responding to a question about the difficulties in addressing hot-button issues such as possible intergroup genetic variation contributing to differences in brain development and/or intelligence:

I hope that such questions can be approached with the same objectivity as that when we study inheritance of bristle number in Drosophila, but I don't expect it soon. There are too many strongly held opinions. I thought Lahn had a clever idea in thinking that the normal alleles of head-reducing mutants might be responsible for evolution of larger heads in human ancestry. Likewise, I think that Cochran et al. are fully entitled to consider the reasons for Jewish intelligence and I found their arguments interesting. In my view it is wrong to say that research in this area -- assuming it is well done -- is out of order. I feel srongly that we should not discourage a line of research because someone might not like a possible outcome.

You can read the two most relevant papers by Lahn and colleagues here and here, as well as just-published criticisms of this work, and a response by Lahn and colleagues. As for the paper by Cochran et al. entitled “Natural History of Ashkenazi Intelligence”, a good summary has been written by Steven Pinker.