An array of human rights documents and decisions address sex, gender and sexual orientation as separate grounds for, for example, discrimination, stereotypes or violence. This article delves into the interrelationship between these three concepts by exploring the European Court of Human Rights’ (ECtHR) judgment X v Poland from the perspective of their different interpretations of sex, gender and sexual orientation as legal categories. By combining queer theories with the Inter-American Court of Human Rights’ (IACtHR) interpretive activity, this paper criticises the ECtHR’s approach. In X v Poland, the ECtHR found a violation of the prohibition of discrimination, arguing that the domestic authorities’ rejection of the applicant’s request to obtain the custody of her child was grounded on her sexual orientation. However, the ECtHR missed the opportunity not only to clearly set out that parents’ sexual orientation does not affect their parental capability, but also (i) to conduct an intersectional analysis of the violation and identify multiple discrimination on the basis of gender and sexual orientation; and, consequently, (ii) to explain the interdependence between these categories. Sex and gender are the preconditions to determine whether one’s sexual orientation meets societal heteronormative expectations. In order to explain the intimate relation between gender and sexual orientation, the investigation relies on performativity as the theory of gender as a reiterated performance, as developed particularly by queer scholars. The identification with one (or more) gender(s) is the result of the interaction between the individual’s personal desire and the socio-cultural norms on gender imposed on the individual. Each person expresses their unique gender(s) in manifold ways, including sexual orientation as the relational encounter between gendered subjectivities. For instance, the IACtHR’s advisory opinion OC-24/17 enshrines a unique conceptualization of sexual orientation as a continuum, i.e. the sentimental and/or sexual attraction to (m)any gender(s) that can change throughout life. The paper concludes that, notwithstanding its conceptual loopholes, X v. Poland remains a landmark decision in that it recognizes the nexus between gender-based stereotypes and discrimination on the basis of sexual orientation.
