When gender reassignment surgery is performed, on males or females, the external genitalia are irrevocably removed; breasts, Testis and penis for instance.
Similar procedures have been done for centuries on females in other cultures in the under-developed world. The labia and clitoris are removed, often crudely, and in a non-clinical setting. In the developed countries, this practice has been criticized and characterized as mutilation.
Ignoring cultural differences, how is sex reassignment surgery as currently practiced, not mutilation? Especially when performed on a minor?