I have a question for you, do you personally know anyone who has struggled with Gender Issues, or their sexuality? I have two brothers both of whom are gay. That is not directly relevant to my point, but I am also friends with a trans man, i.e anatomically born female, but identifies as a male, and has felt this way since he was a young child.
It's not a choice, it's a horrendous battle of confusion, depression, anxiety, self-hatred, self torture, societal norms, conformism and language. This phenomenon cannot be reduced to words expressed by any experts, dictionary definitions, or subjective opinions of people looking from the outside in.

It's not a 'choice' some one makes. Who would choose to put them selves through such hell. My friend battles hatred, yes hatred from total strangers for.........well.......for what is the question. What concern is it to anyone how someone chooses to identify? He has not committed murder, he has not done any harm, only to him self only be listening to the constraints and judgments of people who are not qualified to make them. Everyone is entitled to their opinion of course, and I absolutely respect that. But everyone is also entitled to live as they please, and they do not choose to identify as something else just because, they try that route to try and feel more comfortable with themselves. Everyone gets that little uneasiness when they've gained some weight, or they have a bad bout of achne. Multiply that feeling by a million and then try to imagine not being able to escape it, not really understanding it, just trying to get by the best way you can figure out how.

Is it a mental health problem? Is it a social problem? Is it a spiritual problem? Is it even a problem? I don't know, and i can't say i understand it, because i do not, but I'm not especially bothered by what it is. When there are people out there harming defenceless animals and children and mega atrocities are occurring all over the globe, identifying as one gender over another is not something people should be particularly bothered about.

"A doctor does not need to know what you think you are, a doctor needs to know what sex you are"

If a doctor needs to know what religion you are to ensure your treatment is tailored to your beliefs, beliefs that are nothing to do with science and medicine, in order to make sure that your comfortable, then yes they need to know how you identify, for the same reason.

If you read into the field of Psychoneuroimmunology you can see that research proves that the state of the mind has direct affects on the immune system, thus recovery and infection rates are directly impacted by the whole experience of medical care, including having your ideals and belief's adhered to.

Also most trans people will be on hormone therapy, so no even though the body at still have female genitals, non female hormones could be racing through the body which would affect a whole plethora of medical considerations. Largely it is to do with the state of mind also.

As I said everyone is entitled to their opinion, and it's not something I understand, but I don't need to. I'm quite content in acceptance, it really does not affect my life if there is an additional sign on the bathroom door.

Just thought I would comment to share my views, which largely are present from personal experience of knowing and helping a trans person that's all, as not many people will actually have this experience/perspective.