The Worst Book in the World

DSM-V:  Being transgender is no longer a mental disorder

Arbitrary classification is not science.
In the abscence of evidence of what actually causes transgender identity (or autism and everything else they are changing), neither the original assumption nor the reclassification are based on reality.   It's ALL politics-  territory grabbing and ass covering.

The most appropriate and surely more effective thing to do is to remove all the diagnoses that are based on flying ass monkeys.  But that's all of them.
Treat people for actual medical problems and see what happens.