I'm not sure that parentage matters. When you have powers that defy reality, you have an undeniable superiority. What you seem to be saying, and what I would agree with, is that you can't really argue that mutants are an ethnic group because they don't all share a genetic bloodline back to the first mutant.

But I think it's really hard to claim that someone with the ability to manipulate any and all metal in any way they want does not have an inherent superiority over all non-mutants.