I found one paper describing one case. Is that what you're referring to? If so I'm guessing you haven't had much exposure to biology -- definitions always have

I found one paper describing one case. Is that what you're referring to? If so I'm guessing you haven't had much exposure to biology -- definitions always have counter examples in biology. The important thing is to have simple definitions that get at the core conceptual structure. "Females are XX humans; males are XY humans" is one such definition, questioned only by a small contingent of non scientific social activists in western countries in the last decade or so.