Physical Reality versus our thoughts.

I don’t get it. If I were to say that I was 6 foot two, a quick look at me would tell you that I was either lying, or deluded.
If I said that I was Napoleon Bonaparte a quick look at the calendar, a look at my medical records, or a question posed to me in French would again let you know that I was either deluded, or lying.

if I was 6 ft 2 , weighed 90 pounds, and claimed I was fat, you would tell me to get my finger out of my throat, put a healthy meal down it, and get my fanny to the doctor ASAP!
Virtually any time that I believe something that my physical body says is a lie, it is my brain’s fault, not my body’s.
An exception to the rule about reality being outside of the mind is,  If I told you that despite what my medical records say that I am really a man, and that I was willing to spend thousands of dollars to pay someone to mutilate my body, and ruin a long term marriage to make my body reflect what my mind wants to be true I would be called a hero!
Why would my mind be wrong most of the time, but when it comes to sexual issues the mind is right, and physical reality wrong?