[4Tran]

Both Alto and Ranma have the surname of 早乙女. In Alto's case, it doesn't take someone with gender issues to be annoyed when teased the way he was. From what we know of his character, he's both serious-minded and very goal oriented. Such people often don't take well to getting teased. As far as I can tell, the onnagata thing is just a nifty character hook that allows the audience to easily get into his character.