There are plenty of enculturation reasons too. Doesn't need to have an evolutionary or biological basis.

I don't know if this is true, but intuitively it seems that something is more likely to be ingrained in a culture if there is already a biological basis for the behavior.

I still strongly question that. For instance, it could be that our double-standard expectations of women create more cognitive dissonance - which might impact confidence or give women a sense that whichever choice they make will be judged as "wrong". Or perhaps girls are less likely to be given the benefit of the doubt when they make mistakes in childhood - teaching them to be less resilient or risk-taking - without there being any biological reason to judge them more harshly.