The legalization of sex reassignment surgery in the Islamic Republic of Iran can be analyzed as the result of a secularization process. Regressive dimensions of fiqh exist alongside progressive dimensions regarding issues of sexuality. The analysis of the secularization process used in the medico-judicial protocol of the gender transition leads us to characterize this secularization as a sectorial and heterogeneous techno-secularization. This model of secularization will be analyzed through the history of modernization, drawing on the links between secularization and medicalization, women’s rights, gender relations and Islamic bioethics.