183 General discussion 10 later in life, and long-term effects on mental health, bone mineral density, cardiovascular health, quality of life and, a worry of many, fertility (Heneghan & Jefferson, 2019; Laidlaw et al., 2019b; Malone, Hruz, Mason, & Beck, 2021; Naezer et al., 2021; Richards et al., 2019). Of note, many advocates of the use of early medical treatment share having worries about these topics (Olson-Kennedy et al., 2016; Vrouenraets et al., 2015). Furthermore, critics of the use of PS in transgender adolescents emphasize that it regards a medical intervention with major bodily consequences used for adolescents who are not physically ill (Sadjadi, 2013). Some claim that treatment with PS for transgender adolescents should be curtailed until one is able to apply the same scientific rigor that is required for other medical treatments (Richards et al., 2019). Some however are concerned that bias and politicization will prevent a truthful scientific debate about the interventions for these adolescents (Malone et al., 2021). On the other hand, advocates of the treatment stress the positive results of providing PS to adolescents in the early stages of puberty, provided that the adolescents are eligible for starting this treatment based on the criteria mentioned in two established international transgender guidelines (Coleman et al., 2022; Hembree et al., 2017; see also table 3 which can be found at page 14). Although, according to those criticizing treatment, they may not meet the golden evidence-base standard, various long-term and shorter-term follow-up studies in different parts of the world show positive results regarding the effectiveness of PS, improving the adolescent´s psychological functioning and appearance congruence, and decreasing emotional and behavioural problems (e.g. Chen et al., 2023; Costa et al., 2015; van der Miesen et al., 2020; de Vries et al., 2011a; de Vries et al., 2014). Other relatively large scale prospective longitudinal studies in different parts of the world are in progress (Olson-Kennedy et al., 2019; Reardon, 2016; Tollit et al., 2019). In addition, there is debate about whether every transgender adolescent could profit from treatment in early puberty, or that there is a not earlier recognized developmental pathway of post-puberty onset gender dysphoria. Whether these adolescent profit similarly from early treatment is unclear since still little is known about for example challenges that transgender adolescents who present at an older age with gender dysphoria might face and what effects that might have on, for example, eventually detransitioning (Chen et al., 2020; A. de Vries, 2020; Sevlever & Meyer-Bahlburg, 2019; Turban, Carswell, & Keuroghlian, 2018a). Furthermore, it is stressed that withholding adolescents from PS is not a neutral option and might cause life-long harm (Coleman et al., 2022; Cohen & Gomez-Lobo, 2021; de Vries et al., 2021; Vrouenraets et al., 2015). Providing this treatment in the early stages of puberty ensures that, among others, transgirls do not have to deal with a deepened voice, and masculinization of their face, and transboys do not have to deal with breast development,