== Lewontin and bias == 

 Quote from article: "However, critics (such as the evolutionary geneticist R. C Lewontin) have highlighted serious flaws in twin studies, such as the inability of researchers to separate environmental, genetic, and dialectic effects on twins,[3] and twin studies as a tool for determining the heritability of behavioral traits in humans have been largely abandoned.[citation needed]" 

 Isn't Lewontin known to be ideologically opposed to this subject and thus lie about it? I shall leave it for for someone more knowledgeable than I but if so, then I don't see why his political opinion purporting to be science is relevant. However I think the uncited sentence is false and so I will remove it.