There is no empirical way to verify if someone is actually transgender. In fact, there really is no theoretical way that a person could even be transgender unless one accepts the idea of a non-material soul that is somehow gendered. Whether someone is a male or a female is simply a question of biological definitions of observed reality, just as whether an animal is a dog or a cat is simply a question of biological definitions and observed reality. A man who thinks he is a woman is simply mistaken by definition, just as a man who thinks he is a dog or a cat is mistaken by definition. This is not to say we should not have compassion for people who believe they are transgender and try to help them.