Given his interest in the history of sexuality and his radical denaturalization of dominant understandings of sexual identity, Michel Foucault is a key poststructuralist influence on the development of queer theory. Foucault's understanding that sexuality is a discursive production, rather than an essential human attribute, is part of his larger conceptualization of power as less repressive and negative than productive and generative. That is, rather than characterize power's operation as suppressing our free sexual expression—this misrecognition of power's operation is so widespread that Foucault refers to it as "the repressive hypothesis" (p. 15)—Foucault instead argues that power operates through discourse to produce sexuality as a hidden truth that must be rooted out and specified in all its manifestations:
The society that emerged in the nineteenth century—bourgeois, capitalist, or industrial society, call it what you will—did not confront sex with a fundamental refusal of recognition. On the contrary, it put into operation an entire machinery for producing true discourses concerning it. Not only did it speak of sex and compel everyone to do so; it also set out to formulate the uniform truth of sex. (p. 69)
Identifying this conflation of sex and truth as key to the modern invention of sexuality, Foucault refuses the idea that sexuality can be authoritatively defined, focusing instead on the discursive production of sexuality within regimes of power and knowledge: what is said about it, what relations it generates, how it is experienced, what function it has historically played.
In arguing, first, that sexuality is not an essentially personal attribute but an available cultural category and, second, that it is the effect of power rather than its preexisting object, Foucault's work has been key to the development of queer theory, particularly its capacity to understand itself as a mode of analysis without a defined object.