In this article, we analyse the novel case of Phoenix, a non-binary adult requesting ongoing puberty suppression to permanently prevent the development of secondary sex characteristics, as a way of affirming their gender identity. We argue that the aim of OPS is consistent with the proper goals of medicine to promote well-being, and therefore could ethically be offered to non-binary adults in principle; there are additional equity-based reasons to offer OPS to non-binary adults as a group; and the ethical defensibility (...) of facilitating individual requests for OPS from non-binary adults also depends on other relevant considerations, including the balance of potential benefits over harms for that specific patient, and whether the patient’s request is substantially autonomous. Although the broadly principlist ethical approach we take can be used to analyse other cases of non-binary adults requesting OPS apart from the case we evaluate, we highlight that the outcome will necessarily depend on the individual’s context and values. However, such clinical provision of OPS should ideally be within the context of a properly designed research study with long-term follow-up and open publication of results. (shrink)