There is a lot ethical issues around "transition". Gender dysphoria seems to exist outside the usual practices of medicines. Criteria diagnostics rely on sexists stereotypes and, nowadays, you can't question a patient's "identity" without risking accusations of transphobia and conversion therapy. In other words, proffessionals have to accept trans people's self-diagnosis. Hormones and surgeries must be provided on demand, too. Many trans people seem not to have interest in research regarding what causes dysphoria or alternative treatements despite there is no evidence that "gender affirmement treatment" works as a cure or the many health complications that follow from exogenous hormones and/or surgeries. As result, research is very lacking and heavily politized.

Doctors often also minimize the risk and overstate the results. Many seem to care more about ideology and profit than science and ethics. Many don't seem to care much about all the other co-morbidities that trans identified patients present and "transition" is often sold as a panacea that may resolve all their problems.

Furthermore, I don't know of any other mental health issue that is treated like gender dysphoria. Nobody thinks anorexic people should be given liposuctions, for example.

Another important issue is that after "physical transition" many trans identified individuals become more entitled to be treated as the opposite sex in all aspects.

Finally, when in comes to minors, I don't think "transition" should be allowed at all. Most of them will desist if left alone. However, even if we could tell which children would persist in adulthood, as the judges in the Keira Bell's case said, they are too young to understand all the consequences.