Well then you're being unfair when you ask for conclusive evidence since what you're basically saying here is that the entire field is questionable in its conclusions. Of course, as others have mentioned, transgender isn't something that's only been studied psychologically, but we don't even have to go there. We can make reasonable inferences from the existing data that we have. Even if we don't have "conclusive evidence" that post-traumatic stress disorder is real, we can infer that people like our men and women who serve overseas experience so many traumatic events that it can be reasonable to assume that their condition is one which is real and requires treatment, even if it's hard to establish since it occurs at the level of the brain and is intangible. Likewise, a condition which a certain percentage of the population have admitted has plagued them since infancy and has persisted way into adulthood can be reasonably relied on as being a real distress that is unlikely to be either a "liberal" conspiracy nor a petulant whim. It seems that you, like many other ardent dogmatists here on this forum, are just bothered because this issue touches on taboo subjects that you dislike: sex and gender.