126 Chapter 7 A study from the Netherlands showed that of all adolescents seen at the Amsterdam gender identity clinic, around 75% started with PS and the other 25% did not (Arnoldussen et al., 2020; Arnoldussen et al., 2022b). The vast majority of the adolescents who start PS subsequently start GAMT (e.g., Brik et al., 2020; de Vries, Steensma, Doreleijers, & CohenKettenis, 2011b; Wiepjes et al., 2019). The follow-up studies that are available show that psychological functioning has significantly improved after PS, gender-affirming hormones (GAH) and surgeries (de Vries et al., 2011b; de Vries et al., 2014). Longer-term follow-up data on treatment satisfaction, psychological functioning and possible discontinuation of affirming treatment are currently being collected (no results yet). Previous research has shown that many transgender adolescents seem to experience PS as the first necessary step of a seemingly clear trajectory towards further GAMT, rather than as an opportunity to consider further treatment wishes (Brik et al., 2020). This implies that PS may serve functions that are not mentioned in the guidelines. Little research has examined the motivation to apply for PS from the point of view of adolescents and their parents. Insight into the function of PS according to the adolescents, their parents, and their clinicians will help to adequately support the adolescents in their decision-making process and give them the care and information they need. In addition, functions of PS may vary among adolescents; for those who subsequently start with GAH the function of PS may be different than for those who discontinue PS. To gain more insight into this topic, we have performed a qualitative interview study focusing on the following questions: (1) what function did treatment with PS have for transgender adolescents, their parents, and their clinicians?; and (2) do transgender adolescents who continued to GAMT, adolescents who discontinued PS treatment, their parents, and clinicians have different ideas about the function of PS, and if so, in what sense? METHODS Participants The study was approved by the institutional review board of the Amsterdam University Medical Centres, location VUmc, and the Leiden University Medical Centre (LUMC). Interviews and focus groups were conducted in the context of a larger study on transgender adolescents’ competence to consent to PS and the function of this treatment. Transgender adolescents who proceeded to GAH after PS as well as adolescents who discontinued treatment with PS, and their parents were recruited from the gender identity clinics in Amsterdam and Leiden between January and September 2019. They were interviewed in order to explore their considerations and experiences regarding the function of PS. The same topics were discussed in focus groups with clinicians of the two treatment teams. The Amsterdam and Leiden gender identity clinics were the only two