Genes are important for understanding our behavior. Incredibly important - after all, they code for every protein pertinent to brain function, endocrinology, etc.

Almost always, genes are about potentials and vulnerabilities rather than about determinism.

Brains distinguish between an Us and a Them in a fraction of a second. Subliminal processing of a Them activates the amygdala and insular cortex, brain regions that are all about fear, anxiety, aggression, and disgust.

The frontal cortex doesn't even fully develop until age 25, which is wild!

But if you get chronically, psychosocially stressed, you're going to compromise your health. So, essentially, we've evolved to be smart enough to make ourselves sick.

Importantly, rather than promoting aggression, testosterone promotes whatever is needed to maintain status when challenged.

Only humans invent moralizing gods who monitor our behavior.