People don't have to justify their existence to you by citing scientific studies.
I like that. But... how do you mean?
I guess that I should say something more to give it momentum.
See the OP. The idea that transgender characters need a reason to exist in fiction. That's the latest marginalization tactic from people who never question fiction with abusive characters. Sociopathic characters. Apologists of colonialism and slavery. Warmongers. It's apparently OK to normalize all those through countless works of fiction, but the moment someone tries to do the same for transgender people? That must be "pandering" to those "Tumblr people". Who are presumably some kind of scary creatures of the night, as opposed to decent human beings trying to remind others that not everyone is like them and that's both normal and good.
You sound kind of emotional. This is not a train that will get you far distance. I believe any reasonable human being should at least try to find an excuse for literally taking space in the great universe we live in, not because it is required, but because it is healthy. Nobody is going to persecute anyone for failing at answering that question, because we are all imperfect and nobody knows the endless margins of beginning or end, where do we come from. Each life is precious but that does not mean it should prohibit a man from taking action and simply living own life, because we belong not only to an ideal realm of our identities. There is truth to everything, as we are all shades of God. There is also metaphysical truth to homosexuality, but that does not mean I should consider this truth my part of excuse for literally living.
"find an excuse for literally taking space"
Are you listening to yourself? That's literally the first step towards concentration camps. Not in theory, but in history. There are people still alive who went through that. And guess which people tend to be taken away first. Yeah, I'm allowed to be "emotional" about literal fascism.
No offense, but I'm putting my foot down right here. If you want to continue this conversation, I'll hide the topic at the very least.