Sterilization of children.
The only “transgender” possible is either male to neuter, or female to neuter. The transformation CANNOT proceed further. Worse, it is irreversible, and lasts for whatever remaining lifetime the victim has. There is a scurrilous argument being used, “Would you rather have a dead son than a live trans-daughter?” First of all, the threats of suicide are a negotiating ploy by a troubled adolescent, and very rarely carried out. But secondly, once the alterations are done, if it is more than adopting mannerisms of the opposite sex and dress-up, when the implications of NEVER going back hit, the terrors that induce suicide are much greater and far more certain.
Sterilization of youth and depopulation of the planet on the installment plan. Fortunately, only a small contingent of youth is trapped just this way, but it is an alarming thing for the rest of their cohort to have to deal with.
Plus a lifelong dependency of medical support and its concurrent expense.