Queer theory is a field of post-structuralist critical theory that emerged in the early 1990s out of the fields of queer studies and women's studies. Queer theory includes both queer readings of texts and the theorisation of 'queerness' itself. Heavily influenced by the work of Lauren Berlant, Leo Bersani, Judith Butler, Lee Edelman, Jack Halberstam, David Halperin, José Esteban Muñoz, and Eve Kosofsky Sedgwick, queer theory builds both upon feminist challenges to the idea that gender is part of the essential self and upon gay/lesbian studies' close examination of the socially constructed nature of sexual acts and identities. Whereas gay/lesbian studies focused its inquiries into natural and unnatural behaviour with respect to homosexual behaviour, queer theory expands its focus to encompass any kind of sexual activity or identity that falls into normative and deviant categories. Italian feminist and film theorist Teresa de Lauretis coined the term "queer theory" for a conference she organized at the University of California, Santa Cruz in 1990 and a special issue of Differences: A Journal of Feminist Cultural Studies she edited based on that conference. Queer theory "focuses on mismatches between sex, gender and desire." Queer has been associated most prominently with bisexual, lesbian and gay subjects, but its analytic framework also includes such topics as cross-dressing, intersex, gender ambiguity and gender-corrective surgery. Queer theory's attempted debunking of stable (and correlated) sexes, genders, and sexualities develops out of the specifically lesbian and gay reworking of the post-structuralist figuring of identity as a constellation of multiple and unstable positions. Queer theory examines the constitutive discourses of homosexuality developed in the last century in order to place "queer" in its historical context, and surveys contemporary arguments both for and against this latest terminology.