Then the word would lose all charge of its meaning, my feelings and self identity are not as important as linguistic semantics. I am fine with calling people whatever they want to be called, my only rules are as follows.
1. They do not ask me to change the wording for something with an established meaning.
2. The word they want me to call them either exists and has an established meaning or refers to something that does not already have a word. That is, for example, I could not change what I'd call them, the being of flesh and blood, but I could call them by an abstract label that they'd like to be called, that describes in some way how they think or feel.
3. They do not ask me to call them by a word that already has a different meaning.
I will call a male person a "man" and I will call a female person a "woman", but if there is a word for a male person who identifies as a female person, that follows these rules, I will happily oblige, and the same goes for a female person that identifies as a male person, or a person of either gender that identifies as neither gender.
One of the last things I want to do is hurt feelings, but one of the things that comes before not hurting peoples feelings is keeping the meaning of words universal from one person to the next.
First you mocked me for using the word "decide" implying there was not a choice, now you're telling me it's about labeling for social and/or political reasons?
Let's just go through every single possible or impossible scenario and my feelings on the issue.
Person is born as gender X but seems themselves as Y for the same reasons someone with anorexia would see themselves as fat, a homosixual desires individuals of the same gender or a person with ADD can't keep concentration where a different person could (that is, something in the brain is in some way different (different, but not wrong) from the average person). = I call them gender X, but am happy to acknowledge and respect their feelings and would call them Z (as long as Z is the one established word for that) if they wished but not Y.
Person is born as gender X, is the same as the average individual with seeing themselves as X to start with, but for social and/or political reasons, decides to identify as Y. = I call them X and don't feel very keen on calling them anything else.
Person is born as neither gender X nor Y somehow through some genetic difference from most all people. = Okay, so do we have a word for that? I won't call the person X, I won't call them Y, how about Q? (As long as Q is the proper term.)
Person is born as both gender X and Y somehow through some genetic differences from most all people. = Okay, so do we have a word for that? I won't call the person X, I won't call them Y, how about W? (As long as W is the proper term.)