Zoonosis, the problem is that desistance/detransition is very easy to undercount.
In the German insurance study of nearly 8,000 young people with an F64 gender identity diagnosis, only 36.4% still had the diagnosis five years later. Persistence was under 50% in every age group, and only 27.3% in 15 to 19-year-old females. So the idea that adolescent gender distress is normally fixed for life is not supported by that data. https://pmc.ncbi.nlm.nih.gov/articles/PMC11539877/]
Older follow-up studies of pre-pubertal children also found high desistance. One large follow-up of boys referred for gender identity disorder found only 12.2% persisted, while 87.8% desisted. Across earlier studies, persistence averaged about 17.4%, meaning roughly four out of five did not continue with gender dysphoria into adolescence/adulthood. https://pmc.ncbi.nlm.nih.gov/articles/PMC8039393/]
And the reported detransition rates are almost certainly undercounts, because people vanish from the system. Reuters noted that in one Dutch clinic study, 36% of patients did not return after several years and were simply lost to follow-up. In a UK adolescent referral review, 8.3% no longer identified as gender-diverse, but the authors said that may be an underestimate because another 5.4% moved away or did not follow up. https://www.reuters.com/investigates/special-report/usa-transyouth-outcomes/]
There are obvious reasons people do not report it. They may feel embarrassed, ashamed, stupid, or trapped by what they have already said publicly. They may have changed name, pronouns, friendship groups, school identity, online identity, community, politics, clothes, hair, documents, or even body. Walking that back is not neutral. It is socially costly.
There is also pressure from within queer/trans communities. Reuters reported detransitioners being told to “shut up” and even receiving death threats. That will obviously discourage people from saying: “Actually, this was wrong for me.” https://www.reuters.com/investigates/special-report/usa-transyouth-outcomes/]
A survey of detransitioners found only 13% got help from LGBT organisations during detransition, compared with 51% who had support while transitioning. Over half said they did not feel supported during detransition. Their common reasons included realising the dysphoria was about other issues, health concerns, and transition not relieving the distress. https://segm.org/first_large_study_of_detransitioners]
A JAMA Network Open qualitative study also found people discontinuing or reversing treatment often disengaged from care, avoided clinicians because of shame or anticipated stigma, and described lack of follow-up from clinics as a consistent theme. https://pmc.ncbi.nlm.nih.gov/articles/PMC9315415/]
So no, I don’t think we can honestly say detransition is vanishingly rare. We can say the true rate is uncertain, and probably under-reported because of poor follow-up, bad definitions, social shame, community pressure, and the fact that many people who stop identifying as trans no longer appear in “trans” datasets at all.
That is why I think the sane position is exploratory, whole-person therapy. Not “you are definitely trans”, and not “you are definitely not trans”, but proper therapy that looks at autism, trauma, sexuality, puberty, family dynamics, anxiety, depression, social influence, body image and everything else before anyone gets pushed down a path they may later struggle to leave. Somethign this bill - prevents - do you see?