Rolf Degen

"changed DNA"?

Ideas do change gene frequencies, there is absolutely no doubt about that.

Genes can't cause psychological traits.

And the genes, for example, that make you male or female clearly determine your psychological traits.

Indeed that's hard to argue. Also intelligence when you consider down syndrome and the like.

The debate is about normal variation in 'intelligence', down syndrome is outside that range. It's a disorder.

I agree. All I'm saying is there is a genetic effect on intelligence. You're free to discuss that variation til you're blue in the face.

What's the a priori justification for privileging one system over another?

Could in breeding affect the average health status of a population? Mixed breed dogs often avoid the health problems of purebreds. It seems plausible.