It is a statement of our time that it is considered "therapeutic" to surgically remove healthy organs and regraft them into crude facsimiles of the opposite sex's genitalia. Prior and after this surgical mutilation, the "therapy" involves artificial hormone treatment.
They had a psychiatric problem pre-op, and you know what, they've still got a psychiatric problem post-op. The trouble is, society at large is now expected to play along with it in a form of mass psychosis by pretending the subject has now magically transformed into a man or woman.