I have no idea what you're trying to say and don't think genetics as a factor in cultural diversity has anything to do with the point in question. If eating fish makes you taller, and there's a country called Hypotheticalia with a strong north/south cultural divide where North Hypotheticals eat more fish than South Hypotheticals despite being genetically identical, then controlling for culture may change your results.
If whatever you wanted to say agrees with this, I agree with it; if it disagrees, I disagree with it.
