>Have you considered the possibility that confounding variables exist? I have no doubt that coming from a family where your parents have received a good education makes it much more likely for you to personally also go on to get the same education for example.
Yes.
If you read the citations you will see this is based on twin adoption studies, which control for confounding variables almost perfectly.
I assure you, ever single objection you can think of off the top of your head has been raised and overcome.
The heritability of IQ is not a conclusion psychologists wanted to affirm. It is fact the field was forced to come to from the data, despite the ideological drifts of the last 50 years yearning (or in the case of Stephen Jay Gould outright falsifying data) for the opposite conclusion.