See, that's the problem. It's a psychological condition, which comes with countless subjective standards to determine what it truly is, and whether someone may have it.
So many mental health problems stem from how people perceive things and what they come to believe based on these perceptions. One can (and plausibly does) simply think himself into mental illness. I think allowing people to pursue transition the way they can presently creates too many opportunities for harm without real benefit. I would rather there be a standard made in assessing it (and other ailments) in neuropsychological settings.