One of the reasons we struggle with this is due to the way the brain works to protect us or just to avoid pondering everything endlessly just to get through a day—the brain helps us by making generalizations. I think its the limbic part of the brain that is the most basic. We are wired to make some assumptions like “fire”—you can get burned, “Coffee” —-will make me perk up. So if we originally learned that doctors are male, etc, It might take a while to unlearn that.