Scientific evidence on heritability is inconclusive at this point, from what I understand, there was a recent article on this http://online.wsj.com/article/SB1000142412788732416230457830...?

"People have chosen to ignore the genetics of intelligence for a long time," said Mr. Zhao, who hopes to publish his team's initial findings this summer. "People believe it's a controversial topic, especially in the West. That's not the case in China," where IQ studies are regarded more as a scientific challenge and therefore are easier to fund.