>>12941345sex is biological. gender, and all of the associated societal roles and expectations on how to behave are not.
often times, expectations have some kernel of biological truth to them but are taken to the extreme. for example, women have breasts, but societies like America in the 50's where women were expected to raise the children basically on their own haven't been the norm everywhere throughout history.
and not all societies have a gender binary. some native polynesian societies have the concept of a third gender for example.
and then there's intersex people who occur as often as redheads.
