189 General discussion 10 onset gender dysphoria may be more temporary (Littman, 2019). While others state that the term rapid-onset gender dysphoria was coined to describe a supposedly epidemic of adolescents and young adults coming out as transgender people ‘out of the blue’ due to mental illness and social contagion (Ashley, 2020). The phenomenon of rapid-onset gender dysphoria is receiving increasing attention in lay media and scientific research (e.g. Ashley, 2020; Hutchinson et al., 2020). Further research regarding this phenomenon is needed in order to further substantiate these hypotheses on additional scientific data. Consequences for fertility An area of concern that in more recent years has become increasingly evident for many involved in early medical treatment for transgender minors are the consequences of early medical treatment for fertility (e.g. Laidlaw et al., 2019b; Vrouenraets et al., 2015). Therefore, we have explored this issue in more detail in several of our studies. The effects of PS on gonadal function and the development of secondary sex characteristics are reversible when PS is discontinued (Hembree et al., 2017). However, if adolescents subsequently undergo treatment with GAH and gonadectomy this will result in loss of fertility (de Roo et al., 2016; Hembree et al., 2017; Olson et al., 2011). If minors start treatment with PS at a young age by which they never undergo their endogenous puberty, they will also not be able to pursue fertility preservation (Brik et al., 2019; Hudson et al., 2018). In addition, fertility outcomes may vary depending on birth-assigned sex, and on the type of treatment individuals choose to undergo. For example, not all adolescents pursue gonadectomy (Cheng et al., 2019). Nevertheless, the vast majority of the adolescents who start treatment with PS subsequently proceed to treatment with GAH, with loss of fertility as a possible result (Brik et al., 2020). Nonetheless, preliminary results of a longitudinal study suggest that the negative impact of treatment with GAH on spermatogenesis can be reversed in transwomen. This raises the question whether the previous claims that treatment with GAH for transwomen inevitably leads to permanent loss of fertility are correct (de Nie et al., 2023). Further and larger research is needed to confirm these findings (de Nie et al., 2023). Infertility and concerns about (future) fertility may have a major negative impact on someone’s mental health and quality of life (Carter et al., 2010; Trent et al., 2003). This is in line with the finding that possible loss of fertility as a consequence of PS evoked concerns in several interviewed adolescents, their parents, and all interviewed clinicians (Vrouenraets et al., 2015; Vrouenraets et al., 2022a). On the other hand, a questionnaire study conducted in Canada shows that for the majority of the transgender adolescents fertility is a low current and future life priority (Chiniara, Viner, Palmert, & Bonifacio, 2019). The majority of the transgender adolescents in this and some other studies conducted in the United States, have a wish to become a parent, but are open to alternatives for building a family, like adopting children (Chen et al., 2018; Chiniara et al., 2019). In contrast, one of our studies conducted in the Netherlands shows that only 13% of the 22 participating