Evolved wasn't the diction, choice, and I'm still attempting to find a more suitable word. I do like your use of "cultural construction," I may start sighting time instead of state. Cultural construction was what I was attempting to get at; once a species gets past the point where survival depends on gender differences, any gender divisions become socially constructed. Ants have gender divisions, but it appears that their division is fairly natural in its occurrence and still crucial to survival. I'd say that we've reached a point in our evolution that allows us to diverge from such roles, and do agree that they are contributory to the expected social norms that we currently have.
As annoying as this is, unless my impression is wrong about the consensus, the current sociological outlook has gender differences as being completely socially constructed: Gender as Difference, Gender as Division, Doing Gender, and Genderless. (I'm not versed in the last in the series except for the case of Norrie May-Welby, who is the first person to have an official status as being "genderless").
@LRA, No argument from me, some of the best physicists I know (of) are female. I'm currently wondering what our chapter of SPS (Society of Physics Students) can do about that. Our last president, who is about to graduate, was a girl, but now the entire body of officers consists of only guys; I'm hoping this wont have a negative affect of the state of mind of the incoming class.