I am a firm advocate of any story can be told by any writer. I think words are for everyone... however, it does come with the caveat that with great words come great responsiiblty - and you owe your readers a duty of care to present a fully realised world and fully realised humans rather than cartoon facades.... having said that, simply having a transgender person write a story doesn't help, being trans does not imbue people with magical powers and if they're a sucky writer they'll write a sucky story. Research is the order of the day, research and curiosity. :o)