In Gender Trouble, Judith Butler claims that gender is entirely learned. It is not "natural," but cultural. Gender is not a set of traits you are born with, nor is it a set of characteristics innate to a person's genetic makeup. To her, we become "male" or "female" entirely by imitating how other males or females behave. Thus, a child learns to become a girl by performing all the activities her culture has decided are feminine, such as cooking, cleaning and nurturing. She "performs" her gender. Then, after she has performed actions appropriate to her gender in the eyes of her culture, she is praised and her behavior is reinforced: What a sweet little girl! She loves to take care of her doll! This makes the little girl want to take care of her doll all the more, because it pleases the adults in her life. So she becomes more nurturing. When enough little girls become nurturing because this behavior is praised, people say it is "only natural" for girls to be nurturing. It seems as if all little girls are nurturing! It must be inborn! Likewise with boys. If they pick up a stick and battle an imaginary monster, everyone praises them as "all boy," reinforcing their more aggressive, more physical behavior. When enough boys act this way because they have been praised for doing so, it too begins to seem "natural" or genetic. Butler, however, says, no: gender is entirely performative.
Captialist ideology insists that this performed behavior is "inborn," Butler says, to reinforce the idea that dominating women is natural, not socially constructed. It doesn't want people to know they have a choice. Capitalism can more easily exploit women if it can get them to accept that they "naturally" are weaker, less capable of leading, and less capable in general than men. Capitalist society is relieved of the responsibility of treating or educating women as equals if it can shrug its shoulders and say there is nothing it can do because women are born inferior. Butler says this has occurred because capitalism benefits from exploiting women: why would it want to give up all the free and low cost labor women provide because they have been indoctrinated in the belief such work is natural to them? Likewise, since capitalism relies on armies to protect its goods, it benefits if it can get males to believe they "naturally" want to become soldiers, and not question whether this desire is, in fact, learned.