Watson is a classic example of a clever scientist using his authority outside his domain. He is a molecular biologist, not a geneticist, and certainly not a human evolutionary geneticist. Knowing the structure of DNA doesn't help one bit with assessing the phenotypical results of genetic differences, but it does get your opinions on the front pages of newspapers.

For a far better view of human intelligence, read Stephen Jay Gould's The Mismeasurement of Man,