This is a bigoted word, btw. The implications of calling this someone this should be obvious, but I'll help you. The word is derived from the word "mule", would you want your children called this?
mulatto? bigoted? I didn't know that but I haven't heard the term in ages.. You say this but you did not tell us the "correct terminology?
And btw, my kids can be mule headed - what should I call them? :o)