The misrepresentations of Pinker et al. notwithstanding, I know of no social scientists who deny the importance of studying genetic factors. However, the claim that "more behaviors are genetically determined than we previously thought" is blatantly wrong. Even psychological characteristics that are strongly influenced by genetic factors--e.g., schizophrenia--are not genetically determined. In studies with identical twins, the concordance rate for schizophrenia is quite high--about 50%. This is a much higher rate than for fraternal twins or other sibling pairs, and this clearly supports the claim that schizophrenia is influenced by genetics. However, this same research demonstrates that schizophrenia is not genetically determined: I can have the same DNA as someone who develops schiz, and 50% of the time I do not develop the disorder. Clearly, there must be more going on than genetics here! --And just so with other psychological characteristics.
Miles