In presenting the notion of gender as performance or gender performativity in her "Gender Trouble", Judith Butler holds that forced which operate on the subject create the illusion of heterosexual integrity, that is, the myth according to which someone who is born with certain genitals (e.g., a penis) forms a certain gender identity (e.g., a man) as has sexual desire which is directed towards the opposite sex (women). For Butler this perception assumes that there is congruence between sex (male/female), gender identity (man/women) and the object of sexual desire. Butler asks if this congruence is indeed natural, is it really stable and consistent?. Judith Butler claims that this is a fantasy which disguises itself as a law of natural development, but is in fact a regulating ideal which coerces gender identity upon subjects.
Even when gender is acknowledged (by feminism, sociology or psychoanalysis) as the product of social construction, it is still perceived, according to Judith Butler, as a manifestation of some core identity and a true sexuality of the "self". However Butler holds that gender identity does not express some inner truth, but is rather the product of "stylish repetition of actions", that is, gender is performance. In the notion of gender Performativity Judith Butler argues that our sexual identity is a display we constantly act out. This performativity includes a wide range of behaviors, from the way we talk, walk, perform certain rituals etc., acts that we all keep on performing through the course of our lives, and this performance in what constitutes the meaning of masculine of feminine identities.
At the base of the performative gender identity Judith Butler places her notion of forced heterosexuality. She claims that the seemingly natural division of man/woman is founded on the cultural meta-taboo regarding homosexuality, and on the forced and constant regulation of sexuality within the boundaries of heterosexuality. For Butler, performative masculinity and femininity are defined through heterosexual sexuality, and they serve to ratify the allegedly "naturalness" of this normative sexuality while marginalizing other options of sexuality, desire, identities and behaviors which are casted outside the boundaries of normality.
In criticizing gender identity, rendering it as performative or performativity based, Judith Butler is undermining the distinction between gender and sex. She draws attention to the fact that this distinction suggests that the given (natural) sexual body can "put on" different genders (being the product of social construction). But nevertheless, Butler notes how it regularly assumed that the sexed body must generate a certain gender identity, that is, the performance of gender is assigned to reflect the biological sex and is restricted by it. Judith Butler, however, argues that gender is a discursive mechanism which produces sex as a natural essence which precedes any discourse. For Butler, the body itself is a social construction, and this is due to the fact that discourse regarding the body, sexuality, gender, biology and nature determines what is considered as the body, its boundaries and its meaning.
In regarding gender in terms of performance of performativity, Judith Butler rejects any notion of a category that precedes social discourse. Gender for her is always performed, and this performance of gender is entirely a social matter with identity manifested in performativity.