In the spirit of Albert Einstein, I recently decided to do a "thought experiment".  Not having any skills regarding general relativity or quantum physics, I chose a much more mundane subject.

Suppose I went to a representative of the American medical establishment and said:  "I am Sidney Poitier."  Their response would probably be something like:  "Are you not aware that Sidney Poitier is 6' 2" tall and black and dead?  None of these features describe you at all."

Then I would stand up to my full 5' 4" (with shoes), fold my white arms (with multiple freckles), and say:  "What a great con.  I've got everyone believing that I died.  It was the only way to stop being bugged everywhere I go by adoring fans."

At this point, the medical establishment would decide that since my mental state bears no resemblance to objective reality, I need help to correct my mental problems.

Now, suppose I went to this same representative of the American medical establishment and said:  "I am a woman."  This is in spite of the fact that the Y chromosomes in every cell of my body mark me as a male of the species.  Their response would be something like:  "Oh, a case of gender dysphoria.  We can fix that.  A course of female hormones, a breast augmentation, and a little genital surgery will fix you right up."

Note that in both cases my mental state is out of touch with reality, but in one case the answer is to correct my mental state, and in the other case the answer is to attempt to alter reality.  Can anyone explain to me why two such cases would be treated so differently?

Graphic credit: ParaDox CC BY-SA 2.5 license