The differences between the genders, not sexes, had to be minimized.
Here I am either missing something, or else the author himself has fallen into a Gramscian trap. To employ "gender" as anything other than a grammatical category is to admit the idea that man is somehow self-constructed. If the author wants to point to a willful and destructive blurring of the cultural boundary between male and female behavior, there are ways to say so without conceding the adversary's rhetorical abuses.