Within the last thirty years or so, genetic determinism has become en vogue again. But everyone with some knowledge in biology knows that DNA codes for proteins and that in eukaryotic organisms, DNA can be spliced which gives rise to the possibility that a single gene codes for more than one gene.
Genetic determinism also ignores epigenetics, the influence of the environment on the cell and its DNA processing. Thus, the argument that IQ, mental illness etc. are "genetic per se" becomes a non-sensical assertion.