Or maybe it's just what HAPPENS in real life when you have a son and a daughter, and it's effects can be seem on a societal level through, for instance, the number of male vs female hard science college applicants for instance. Different genders have different interests on AVERAGE. The fact that nature doesn't conform to a idealized view of an equal world does not make it "wrong".
equality of outcome vs equality of opportunity. you are never going to get the first because psychology and biology you can only provide for the second.