In my research, nine participants had various body modifi cation technologies as National Health Service (NHS) patients. Gregory who could not
have any surgeries was prescribed hormones on the NHS, and two other transmen had decided not to receive body modifi cation procedures at the time of their interviews. Ten private patients had all undergone various body modifi cations. Addressing participants’ narratives phenomenologically-that is a study of experiences, actions and practices and their meanings (Heinamaa 1997)—this chapter explores how participants understand and negotiate their ‘authentic’ subject positions when seeking body modifi - cation and legal recognition. The fi rst aim of this chapter is to refrain from falling into the trap of reducing authenticity to essentialism, which rests on a biological notion of a core ‘sex’ being the natural basis for ‘gender.’ Secondly, I do not want to reduce ‘authenticity’ to poststructuralist understandings of gender identity formation, in which subjects are often seen as passive and culturally determined by coercive forces, which constitute their mental and behavioural characteristics. I argue that we should regard transsexual subjectivities as intentionally ‘situational’ (Rubin 2003) and understand the agentic negotiations that are intrinsic to trans subjectivity, to get at a deeper understanding of how the medicolegal fi elds are negotiated in the UK.