Heteronormativity describes the hegemonial social norm which justifies the binary gender norm as biologic by assigning gender on the basis of physical aspects. The binary gender norm only recognises two genders, male and female, and defines heterosexuality, the sexual attraction between those two genders, as natural. Heteronormativity defines the non-existence of further genders besides cis man and cis woman. The word cis describes, as an adjective, the gender identity which one was assigned at birth.

Everyone, for example trans*, intersex or non-heterosexual people, who do not meet the expectations of the binary gender norm, are defined as different from alleged standard. Therefore, heteronormativity structures powers between genders and sexualities. Non-conformance from the alleged norm will be viewed as negative and lead to unequal treatment. The devaluation of people whose identity does not equal the heteronormative categories of gender roles, gender relations and sexuality, is called hetero sexism.

At the beginning of the 1990’s, the US-American philosopher and gender scientist Judith Butler describes in the publication ‘’Gender Trouble’’, that the category sex is also constructed. For Butler this means that the categorisations of bodies in male and female are only based on an imaginary categorisation and assignment without natural legitimation. The construct of the heteronormativity is supported by the assumption of a supposed sex biologism. This means the equalisation of, for example, organs, hormones or chromosomes with the sex and supports the assignment of people based of physical characteristics.

This assignment should be reconsidered as gender, as well as gender body, exist in different variations. Butler’s theory is intensively discussed in scientific discourses and part of gender studies.