137 Perceptions on the function of puberty suppression of transgender adolescents who continued or discontinued treatment, their parents, and clinicians 7 clinicians have the feeling they need to ‘slow down’ the adolescents who seem to have set GAMT as their final ‘goal’, in order to make sure that each step is carefully considered. Even though research shows mostly positive effects of PS, some of the long-term effects of the treatment are still unknown (Biggs, 2021; Giordano & Holm, 2020; Harris et al., 2019; Klaver et al., 2018; 2020; Klink et al., 2015; Schagen, Wouters, Cohen-Kettenis, Gooren, & Hannema, 2020). Concerns have been raised about adolescents regretting the treatment later in life, and about the effects of GnRHa on cognitive, physical and psychosocial development (Ashley, 2019; Chen & Simons, 2018; A. de Vries, 2020; Kaltiala-Heino, Bergman, Työläjärvi, & Frisén, 2018; Laidlaw et al., 2019b; Vrouenraets et al., 2015; Wren, 2019). If PS is regarded as the first step of GAMT, children from the age of 10 make decisions with life-long consequences. One of the most pressing concerns is the possible loss of fertility due to adolescents ‘automatically’ proceeding to GAH and possibly gonadectomy and the fact that these adolescents will never undergo the puberty of their birth-assigned sex (Hudson et al., 2018). Loss of fertility, as well as concerns about (future) fertility may have a significant negative impact on quality of life and psychosocial well-being (Brik et al., 2019; Carter et al., 2010; Gorman, Su, Robert, Dominick, & Malcarne, 2015; Trent et al., 2003; Wenzel et al., 2005). On the other hand, one should keep in mind that even if treatment with PS might have harmful effects, refraining from intervention might have harmful effects as well (de Vries et al., 2021). In conclusion, the reasons to start PS and the functions of this treatment for transgender adolescents described in the international guidelines are only partly in line with those reported by the adolescents themselves. They overlap to a larger extent with reasons and functions as mentioned by parents, and are largely in line with those reported by clinicians. The purpose with which children, adolescents and parents entered a gender identity clinic in the late 1990s and early 2000s, when the protocol for diagnostic assessment and treatment was drawn up, may be different from the purpose with which they enter a clinic nowadays and may also be different in other countries and contexts. Previously, families may have been ‘confused’ by the situation and the gender non-conforming feelings of the child. They may have wanted support in their search for a way to help the child. At that time, an extended diagnostic period through PS was an ideal option. At the present time, families who enter a clinic are much better informed through the internet, media and peers, and many will have a clear idea of the diagnosis and their treatment wishes. An extended diagnostic period to explore the possibility of pursuing GAMT might therefore not be appropriate for all those who currently enter a gender identity clinic. In that respect, the protocol could be modified to provide help that is more personalized and customized, taking into account someone’s purpose and thoughts. For example, one might consider following the treatment protocol for transgender adults, i.e., skipping PS and starting GAMT immediately after the diagnostic trajectory, in some cases such as older transgender adolescents who have experienced gender non-conforming feelings from an early age, if