This is something really difficult to know, specially because genetic differences can shape behaviors that can be natural selected creating a reinforced loop that reflexes on culture and upbringing.
Very good point. But I'd like to get an accurate answer from science in general, I don't see why more effort shouldn't be put into finding the reason behind what's discussed here. culture and upbringing is a mix of biological tendencies and imposed constructs, and I'd like to know which is which.