His scientist's errors, doubting their credibility

not knowing this
https://en.wikipedia.org/wiki/Central_dogma_of_molecular_biology

Correlation isnt causation, but it is still evidence. And we arent seeing these powerful predictive correlations or variances with environmental explanations. You can say twin studies are imperfect, but the trend they demonstrate is clear. The direction is clear by comparing di and mono, toward more genetic influence.  And they remove the big environmental factors, making it unlikely the rest is hiding behind what remains, which seems to be the only argument against them, unspecified as it is. Stereotype threat is usually the biggest, which is bunk. The idea that you can pull back all the evidence for these genetic findings based on minor criticism is silly. Statistical corrections are needed of course, because twin studies tend to not give twins to poor families as that is unethical
https://msutwinstudies.com/why-twin-studies/
http://econlog.econlib.org/archives/2011/08/are_twin_studie.html

Mocking Aydin when she explained this stuff to Devil's Advocate, or tried to.