81 Medical decision‑making competence regarding puberty suppression: perceptions of transgender adolescents, their parents and clinicians 5 number of individuals that discontinued PS), and (c) had discontinued PS treatment. Out of 1015 adolescents diagnosed with gender dysphoria between 2000 and 2018 at the Amsterdam or Leiden gender identity clinic, twenty adolescents in total were eligible. Eight adolescents could not be reached, mostly because their contact details were no longer up to date. One was not contacted because he had previously indicated that he did not want to be approached for research purposes. Two adolescents were not contacted because their clinician thought this was inappropriate due to, among others, comorbid mental health difficulties. Nine adolescents were asked to participate. Two adolescents declined without giving a reason, one parent did not want her child to participate because she did think that was not in the child’s best interest, and six adolescents agreed to participate. Characteristics of the two groups of adolescents are presented in table 9. Table 9. Characteristics of participating adolescents Variables Adolescents who discontinued treatment Adolescents who continued treatment n 6 8 Birth-assigned girls 5a 4 Birth-assigned boys 1b 4 Age during interview (median; range) (years) 17.5; 14-27 17.9; 15-18 Age when visiting gender identity clinic for the first time (median; range) (years) 14.3; 11-15 11.3; 10-13 Age start PS (median; range) (years) 15.2; 12-17 12.3; 10-14 Duration of PS (median; range) (months) 10; 1-14 35; 21-48 Duration diagnostic trajectory before starting PS treatment (median; range) (months)c 10; 6-22 9; 6-12 Full-scale IQ (median; range) 100; 98-124 104; 76-132 PS refers to treatment with puberty suppression. a Two adolescents identified as transboy, one as a-gender, one as genderfluid, and one as cis-gender girl at the time of the interview. b Gender identity at the time of the interview: a-gender. c Diagnostic trajectory before starting PS treatment; In the Netherlands, transgender adolescents undergo a diagnostic trajectory, consisting of psycho-diagnostic assessment and several sessions with a mental health provider over a longer period of time, when assessing eligibility for PS. The parents of all interviewed adolescents who continued treatment were asked to participate (group 3). Eight parents (seven biological mothers and one biological father) agreed. Four parents (group 4; three biological mothers and one adoptive mother) of adolescents who had discontinued treatment were asked to participate in the study and all agreed. The other parents were not asked because of logistic reasons (e.g. they could not be reached by phone in time prior to the appointment).