The difference between men and women on a basic biological level is based completely on hormones; men have higher levels of testosterone and women have elevated estrogen.  But I think that most of the social stigmas attached to the biological differences are a social construct.  It's a bit like social Darwinism, in which people associate things that have occurred due to evolution or biology with arbitrary traits such as economic status.  The traits become a self-fulfilling prophecy; we expect certain behavioral habits from men and women, and when we condition them to exhibit these traits, we are only validating our own expectations.  I think that there can be a certain level of control in the degree to which we let the biological traits affect society.