191 General discussion 10 practices for engaging in fertility preservation counselling with transgender adolescents and their parents is recommended in order to give them adequate information and support in considering fertility preservation (Tishelman et al., 2019). Future research on alternatives for fertility preservation options which are less psychologically burdensome for the transgender adolescents and their parents, which could be used to facilitate fertility preservation, is recommended (Brik et al., 2019). One such option that is currently investigated, is the provision of TESE (Testicular Sperm Extraction) for transgirls in early stages of puberty (e.g. Adeleye, Stark, Jalalian, Mok-Lin, & Smith, 2021). Finally, further research regarding the possible positive and harmful psychological impact of the fertility preservation procedures would also be valuable (Baram et al., 2019; Chen & Simons, 2018). Perceived functions of treatment with puberty suppression In addition to the possible harmful consequences of starting or refraining from treatment with PS, the functions treatment with PS has for the adolescents, their parents, and their clinicians should also be taken into account when considering starting or refraining from PS. Treatment for transgender adolescents with PS was developed for two main reasons: first, to ‘pause’ the development of sexual sex characteristics in order to expand the exploration and assessment phase (Delemarre-van de Waal & Cohen-Kettenis, 2006). In that way adolescents have ‘extra’ time to explore their options, and experience living in the affirmed gender role, before pursuing GAMT by means of treatment with GAH and/ or surgery, with (partially) irreversible effects. Secondly, the physical appearance will be more satisfactory and congruent to the experienced gender when starting PS in the early stages of puberty compared to PS in later puberty. Furthermore, in that way, some surgery such as mastectomy may not be necessary or less invasive because development of secondary sex characteristics is prevented (Coleman et al., 2022; Hembree et al., 2017; van de Grift et al., 2020). Even though the two established international transgender guidelines describe these and other reasons to use treatment with PS for transgender adolescents, little is known about the functions of PS as reported by the transgender adolescents themselves, their parents, and their clinicians. Two of our studies show that many transgender adolescents experience the function of treatment with PS as the first necessary step of a seemingly clear trajectory towards further gender-affirming interventions, rather than as an opportunity to explore and consider further treatment wishes (Brik et al., 2020; Vrouenraets et al., 2022b). This suggests that treatment with PS may serve other functions than the ones mentioned in the established international transgender guidelines (Vrouenraets et al., 2022b). Insight into the perceived functions of PS would help to adequately support adolescents in their decision-making process and give them the care they need. In line with one of the reasons to start PS mentioned in the established international transgender guidelines, the findings of one of our interview studies and other studies