Children as young as 16 have had the surgery.
https://apnews.com/article/gender-transition-treatment-guidelines-9dbe54f670a3a0f5f2831c2bf14f9bbb
https://apnews.com/article/gender-transition-treatment-guidelines-9dbe54f670a3a0f5f2831c2bf14f9bbb
The update is based on expert opinion and a review of scientific evidence on the benefits and harms of transgender medical treatment in teens whose gender identity doesn’t match the sex they were assigned at birth, the group said. Such evidence is limited but has grown in the last decade, the group said, with studies suggesting the treatments can improve psychological well-being and reduce suicidal behavior.
Since I'm not a scientist who specializes in that sort of thing, I'll defer to the people who are.
Plus, it's still the same as I described, namely that such treatments are only started after the patient has cleared several hurdles (such as extensive counseling, doctors' evaluations, and parental consent). So I agree that these decisions are best made by the families and their doctors.
After all, most of us would get pretty upset if the federal government kept intervening in our most personal medical decisions and issues, so we should allow other Americans the same consideration, freedom, and liberty, even when we may disagree with those decisions.