> Regarding the second, it could be that the women were studying more, and thus not represent a genetic trait. In order to settle whether differences are geneti

> Regarding the second, it could be that the women were studying more, and thus not represent a genetic trait. In order to settle whether differences are genetic, you would have to compare performance from the same amount of effort. I think this is an important objection, but you stop far shy of its true implication. If just studying more would skew the results, then you cannot reasonably say that the method used has any significant power to detect the influence genetic traits. What is tested in a standardised test is arguably the combined effect of societal environment and genes, and considering that the field of the interaction between gene expression and the host environment (Epigenetics) is only just starting, even the genetic component might not be some static contribution.