<p><br />It is commonly accepted that gender matters (whether cisgender, transgender/trans*, gender non-binary, genderfluid, gender queer, agender, or other) and many are raising awareness about the fact that gender always seems to matter. That gender matters, and always matters, does not necessarily mean, however, that gender needs to be authenticated or endorsed by the state.</p><p>In fact, based on a feminist and queer reading of human rights, this interdisciplinary article asserts that state-sponsored sex/gender assignment through the practice of sex/gender registration must halt. It argues that mandatory (binary) sex/gender registration disproportionately infringes the emerging right to gender identity autonomy and the right to the legal recognition thereof. Most often, our Western heterosexual cultural system of gender, which posits the existence of two oppositional and complementary gender identities, anchored in so-called natural and binary sex, goes hand in hand with material and discursive forms of violence and entails various forms of unequal power dynamics. Hegemonic in nature, the heterosexual cultural system of gender pervasively regulates many (if not every) aspects of all bodies’ lives and being, including by legal means. The law upholds and certifies that specific gender regime, inter alia, by assigning a sex to individuals at birth (through the registration of a claimed evident, objective, natural element to be found on or in the body by inspection). Policies of mandatory (binary) sex/gender registration therefore constitute the cornerstone of the legalisation of the heterosexual cultural system of gender, which produces not only the conventional feminine and masculine gender identity (i.e. women and men) but also sex (i.e. females and males).</p><p>This article suggests that, as long as the law refuses to go beyond the compulsory male/female (or even male/female/other) framework, it will be complicit in upholding the undesired consequences of the heterosexual cultural system of gender, which affect all persons of whatever gender or physical features. Therefore, undoing remaining forms of global gender injustice, as well as respecting, protecting and fulfilling human rights relating to gender identity, requires the abolishment of sex/gender registration instead of expanding the available gender markers. Indeed, this article finds that current state practices do not pursue a legitimate aim, and even if they do, mandatory sex/gender registration does not pass the proportionality test that is required in the assessment of restrictions of fundamental rights. A human rights analysis of official sex/gender in the age of gender self-determination finds mandatory sex/gender registration to be a disproportionate measure and recommends that states change their current practices. Doing so would be beneficial to cisgender and trans* individuals alike.</p>