I have a feeling I'm being trolled, but I can't resist. Gender is a social product, and like all social products is built from material elements (e.g., DNA). Thought experiment: take away all the cultural distinctions, socialization, and endless talk and behavior that bifurcate people into men and women. What is left? In a social and practical sense, there are no longer "men" and "women". People in that nongendered society would consider dividing people up based on sex chromosomes to be arbitrary and silly, like people in our society would react to claims about the innate superiority or inferiority of men with male pattern baldness or blue eyes. --Any biological differences you can observe between people or groups of people only have social meaning and importance because of social relations (e.g., the differing importance of the same skin color depending on the historical and cultural moment).
Judith Butler is good on this (Gender trouble); sociologists like Goffman and Garfinkel made this point fifty years ago. Soc 101.
Miles