Example(s): What if you went to you're mom's house and she wanted to kill you? Would she have that right?
Why you shouldn't use it: Personhood is the state of having rights; basically, this is circular logic.
Exceptions to this prohibition: Arguments where personhood is a given. For example, arguing against abortion in case of rape. Also explaining how you think, not persuasively. Also, to get the discussion back to the issue of personhood.