
She argued that gender is not what you are but what you do — and that doing it differently is where freedom begins.
Butler's Gender Trouble, published in 1990, made one argument with long reverberations: gender is performative. This does not mean gender is a performance you could simply stop giving, but that it is produced through repeated acts — what you say, how you move, what you wear, what you do — and has no prior nature it expresses. Sex itself, she argued, is not the natural bedrock on which gender is culturally built; both are produced by the norms that regulate bodies. The implication was that because gender is made through repetition, it can be unmade — or made differently. The argument drew on Austin's philosophy of speech acts, Foucault's genealogy, and psychoanalytic theory. She has extended it since to questions of precarity, grievability, and the politics of mourning — asking which lives are considered lives worth protecting, and whose deaths count as deaths worth grieving.

“Gender is not something that one is, it is something one does, an act in the most theatrical sense.”
“Precarity is a shared condition, and politics is what we do in response to it.”
Published in 1990, Gender Trouble challenged both feminist theory and cultural assumptions about sex and gender. Butler argued that neither sex nor gender are prior to culture: both are produced through the repetition of norms. The book became the founding text of queer theory and one of the most cited works in the humanities.
Butler took de Beauvoir's claim that 'one is not born but becomes a woman' further than de Beauvoir intended: not just gender roles but the categories of sex themselves are culturally constituted and performatively maintained.