The thesis deals with the normative discourse of transsexuality, both from a general cultural- historical perspective in the context of Western science and medicine and more specifically in the context of Czech sexology. On a detailed analysis of the publication Transsexualita: Diagnostika a léčba (Transsexuality: Diagnostics and Treatment), I illustrate the currently dominant conceptualization of transgender and/or transsexuality as a disorder, which, due to its normative influence, predetermines not only the possibilities of (self)identification available to trans* people in the Czech Republic, but also their treatment by Czech society and state institutions (e.g. in the conditions to be met for legal gender recognition, which still inclu...