The study is of particular interest given the great speculation that surrounds this issue, especially among children and young people. The study aims to demonstrate, with a methodology that is more than adequate, that transgender people who begin their transition in childhood-adolescence do not give up. By following a cohort, it shows how almost all adolescents who began their care with hormone blockers at puberty later continued with hormone treatment in accordance with their gender identity. It also shows how this trend, both in patients seeking care and the proportion who continued with treatment, has not changed from more than ten years ago. 

The study complements previous studies in this line that have already shown that there was no scientific evidence to support the suspicion of the supposed discontinuation of hormone treatment in adolescents. It also shows that there are no differences in the age at which the transition to hormone blockers began, which is another of the arguments that are usually used against the care of transgender minors.  

Regarding the limitations of the study, it is a study carried out in a single centre which, however, has been caring for trans children for more than twenty years. Another limitation is that the assessment of the continuity of treatment is made by crossing the data of those people in that centre who started hormone blocking at puberty with the centralised data on hormone prescription. In this way it was found that 2 % had no hormone prescription after years of using the blockade at puberty. Since this was done through data mining, it is impossible to know the reasons why the 2% did not continue hormones (it could be due to adverse effects or a desire to make a non-medicalised transition, among others).  

Finally, the study uses the term "gender dysphoria", which is no longer in use due to WHO recommendations. However, it may be useful in this study to clarify that it includes patients who expressed a desire to transition with hormonal support (the study does not mention patients who transition without hormonal support). 

The main contribution of this study is to shed light with evidence in a field in which there is an abundance of unipersonal voices, but with great media repercussions, that question the gender identity of trans children and the health actions in this regard. In contrast to opinions that claim that adolescent trans people "regret" their transition and that trans identity is "a fad", this article presents scientific evidence that shows that trans children almost entirely maintain their treatment after adolescence. 

The management of gender incongruence in adolescence is a highly complex situation and until a few years ago we did not have robust evidence on some issues such as Rapid Onset Gender Dysphoria (ROGD) (description of trans minors as a consequence of social contagion, which is not a medical diagnosis), the safety of hormone treatments initiated at puberty and desistance (which consists of changing the initially manifested sense of identity) or detransition (consisting of reversing the changes made in the gender reassignment process, whether medical, social or administrative). 

Regarding the DGIR, Bauer published a study in April 2022 that attempted to test the hypothesis of social contagion in transgender minors and that they are "adolescents with comorbid mental health problems". Their results did not confirm the existence of DGIR and did confirm a positive impact on the mental health of adolescents on gender affirming hormone treatment.  

In relation to puberty blockers (GnRH analogues - aGnRH), for more than fifteen years there has been knowledge of their efficacy and the absence of serious adverse effects in their use in children with central precocious puberty. Experience in trans children is more limited, but appears to be similar. Recent work has suggested that growth patterns of trans children with puberty blockers are similar to those reported for prepubertal cisgender children. The use of aGnRH in trans children has also been shown to mitigate the risk of depression, anxiety and suicidal tendencies. 

Van der Loos' study published today in The Lancet Child & Adolescent Health adds further scientific evidence to the question of how many trans adolescents who started hormone treatment in adolescence continue treatment into adulthood. 

The Gender Identity Unit (GIDU) of the Amsterdam UMC is a world leader in all aspects of transgender medicine and is governed by protocolised actions. It has one of the best registries related to the biopsychosocial approach to transgender people. This is reflected in the quality of the data and methodology of the study, and therefore of its conclusions. 

In 2022, Butler answered the question for the first time and found that 95% of trans children who started hormone treatment in adolescence continued it into adulthood.   

In the WBU IGU study, 98% of trans adolescents who started hormone treatment in adolescence continued it into adulthood.  

A limitation of this study is the fact that the prescription of hormone treatment does not necessarily translate into continuation of hormones. This is a limitation of all registry-based studies and may overestimate the results.  

Another limitation of the study was the failure to find the reasons why 2% stopped hormone treatment. Regarding the 2% of transgender people who were untreated, the researchers reflected that it cannot be concluded that these people dropped out or became untransitioned. These individuals could have stopped hormone treatment for a number of plausible reasons for treatment discontinuation, such as lack of knowledge about the importance of continued hormone treatment after gonadectomy (following gender confirmation surgery) or adverse effects of medication, or that they have non-binary identities. 

In any case, the results of van der Loos' work are in line with the results of previous studies and provide evidence in this field that supports the current approach to transgender children. Thus, the results of the Amsterdam UMC IGU study confirm that the initiation of hormone treatment in trans adolescents has a high rate of continuation into adulthood (98%), providing health professionals with evidence to reassure them about the results of the current approach. 

These findings can and should help and guide the current public and legal debate on the initiation of medical treatment in transgender minors. 

An important bias is that they include at least three months of treatment with blockers. This treatment time is not from Tanner stage II-III (around 12-13 years of age) and up to 16 years of age, where oestrogens or testosterone were added. Blockers have to be used from Tanner stage II, when children are between 11 and 12 years old. At that age, three months does not block puberty, it is already very advanced. 

Another bias is that in the cohort the proportions of sex assigned at birth are opposite to the usual. There were always more trans girls than trans boys, about two thirds, and now it has changed: 31% are transitioning from boy to girl (assigned male at birth), and the other 69% are transitioning from girl to boy.