Under influence of radical lesbianism, radical feminism and Foucault s rejection to the repressive hypothesis of sexuality, the queer theory has developed as a critique to hegemonic discourses of gender identity. In facing medical-psychiatric reports considering pathological the various non-heterosexual behaviors, the queer theory seeks to destabilize current notions about gender that comprehend it on an essentialist way. The queer point of view allows an analysis on legal regulation of gay, lesbian and transgender status in Brazil, pointing out inconsistencies in this regulation and its most harmful effects that are unprotection and unequal treatment to these people before the law. Two cases seem greatly highlight the queer criticism: the same-sex marriage and the legal regime of gender reassignment. The scope of this work is to combine the thought of the authors Eve Sedgwick and Judith Butler, that are considered precursors of the queer theory, in order to explain inconsistencies in the legal treatment of LGBTI Brazilian population, especially with regard to the possibility of marriage and gender reassignment.