Fair enough.
How do you propose we "diagnose" this condition?
Is that even possible?
Sure is. This is the only self-diagnosed medical condition that I am aware of. Even my doctors (internist, endocrinologist, two therapists) agree.
What if the diagnosis is wrong?
If we are wrong, we usually find out during therapy, which is required if we intend to transition the "right" way. Any changes are reversible in early stages. And in general, hormone replacement therapy is diagnostic in itself. If you are meant to be the opposite gender, the new hormones make you feel good and "right". If not, you will tend to come unglued, so to speak. It will feel "wrong".
What is this therapy you speak of?
Therapy is just what it sounds like. Therapy with a trained gender specialist. Yes, there is training for that and no, not just ANY therapist will do, it needs to be a specialist.
This is an example of a trained therapist. If the therapist is not trained to deal with trans issues, they should refuse treatment and refer the patient to a more qualified person.
I'm honestly just asking.