85 Medical decision‑making competence regarding puberty suppression: perceptions of transgender adolescents, their parents and clinicians 5 Apart from the possible loss of fertility, adolescents, both continuers and discontinuers, parents, and clinicians mentioned other consequences of PS that are difficult to understand and appreciate for adolescents prior to the start of treatment. For example, several adolescents mentioned that they had not realised their peers would undergo pubertal development while they stood ‘still’ as their puberty was suppressed and that they found this difficult to cope with. This had a negative psychological impact. “I did have the feeling that I stood still while the rest [my peers who did go through pubertal development] went on [...] [Before starting the treatment with puberty suppression] I had not thought very much about what that could do to you mentally. [...] I was quite depressed during that time. And [...] I think that it [the fact that I had the feeling I stood still while my peers went through their pubertal development] also played a part in how I felt [depressed] at the time. I had not foreseen that beforehand.” - Interview with a transgirl who continued PS; age at start PS: 12.0; age at interview: 18.1 Additionally, some clinicians stated that they think that it is difficult for an obese adolescent to understand and appreciate the impact of not being eligible to undergo certain surgeries following PS and GAH if they were to remain obese.5 Uncertainties regarding the long-term effects of puberty suppression Some parents stated that they themselves knew little about the consequences of the treatment. One parent indicated that it is a challenge that no one can ever tell what the outcome would have been without medical treatment. Furthermore, some parents stated that they themselves would never take medication with unknown long-term effects. “[Starting the treatment with puberty suppression was] a bit scary for all of us in the sense that we did not know whether we were doing the right thing or whether we were going to stuff our child full of things of which you do not know the consequences yet.” - Interview with a parent of a transboy who continued PS; age at start PS: 10.9; age at interview: 17.6 “What I think is difficult about puberty suppression is that you do not know exactly what you’re suppressing; you do not know what she [my daughter] would have become if she had not used that [treatment with pubertal suppression] [...] you do not know what you’re inhibiting. [...] Yes, you [know that you] suppress puberty, but 5 According to the protocol as used in the Dutch gender identity clinics the upper limit of the person’s body mass index (BMI) to be eligible for for example mastectomy is 35 kg/m2, and for phalloplasty and vaginoplasty the upper limit is a BMI of 30 kg/m2.