Criminal offending is not the norm and gender dysphoria is comparatively rare. The combination of the two, accordingly, is so infrequent that there is little published literature, and none of it even attempts statistical validity. In this specialised element of an already specialised field within a medical specialism, any learning must inevitably, perhaps, be experiential. Experience grows patient by patient, and knowledge and judgement correspondingly improve. It is for this reason that trans folk in forensic settings present the greatest challenges and require every ounce of multidisciplinary attention that can be afforded. This chapter does not specifically cover trans people in the secure estate who have an autistic condition or an intellectual disability (see Chapter 7, Autistic Spectrum Conditions and Intellectual Disability); however, the principles outlined here may apply also for those who have been diverted into the mental health system, or who are in the secure mental health estate as discussed later.