What differentiation? A cross dresser wears something that can only realistically be worn by the opposite gender. That really boils down to two items; the bra, and the jockstrap. Even then, there are men who actually need to wear a bra (gynecomastia aka "moobs"); fortunately, I'm not one of them! I can't think of a single example of how a woman would need a jockstrap though.
Other than those 2 examples, its just clothing that fits anyone. Back in the day, women who wore pants were called "crossdressers" too, even though they really weren't.