If specific genes exist in humans that affect intelligence and/or brain size they will be found very soon. I work in a lab at a major research university that is culling racial differences in the human genome and making transgenic "africanized" and "europeanized" mice based on these differences. If these mice have significant differences in traits related to intelligence the results will be indisputable, unlike correlative studies based on human populations living under different socioeconomic conditions. This can of worms is about to explode and I'm not sure if people are ready for the consequences.