So feminism assumes that it is due to society that women can become pregnant and men can't? Most feminists I know are normal-reasonable-people on your dichotomy, though you also ignore the fact that the category of whether differences are desireable and whether they can be influenced are far more interesting and important than whether they are at present mostly due to society or biology. I know people have a strange tendency to act as if things due to society can be trivially changed by collective whim while biology is eternal and immutable, but however common such a view, it is clearly absurd. Medicine can make all sorts of adjustments to our biology, while social engineers have historically been more likely to have unintended effects or no effect at all than they have been to successfully transform their societies in the ways they desire.