A widely held rights-based view asserts that individuals should be permitted to self-designate characteristics such as race and gender. But some argue that there are opinions that oppose the use only of self-designation, and that these should not be ignored. Kasher and Rubinstein (Logique Anal 160:385–395, 1997) demonstrated that the latter view is equivalent to accepting that one or more of five conditions must be violated. This paper extends their analysis to allow for more than two categories, and focuses on (...) simplifying the conditions without jeopardising their conclusion. In particular, we use significantly weaker conditions of independence and of symmetry than are common in other extensions of the original proposition. (shrink)