In international human rights law (IHRL), women’s rights have been a staple of UN activity since the 1990s. LGBT* rights have entered the UN stage more recently via focus on non-discrimination on the basis of sexual orientation and developments such as the Yogyakarta Principles. Women’s and LGBT* rights, however, continue to be perceived as distinct. In this paper, I argue for a joined-up approach which I term ‘sex/gender’ rights. This would integrate the concerns of women and LGBT* persons, recognising gender as a technology of power affecting many identities and relations. This approach is not one that I argue to be falsely imposed on IHRL. Rather, drawing from Elizabeth Grosz’s reading of Charles Darwin, such a development can be considered as part of the ongoing evolution of IHRL. This conception of evolution is untimely – moving backwards as well as forwards – and may involve a return to reconsider the foundational ideas of ‘sex’ and ‘gender’ and re-approach rights accordingly.