See, what you are doing is reverting to the intellectually dishonest "anything's possible" gambit.
We do in fact know what sorts of variants can and cannot reproduce, which is why we do not have chimerae running around all over the place. You act as though the science of modern genetics doesn't have a century of research to determine what does and does not occur.
No, you misread me. I'm not merely saying it's "possible" that chromosome numbers can change without eliminating (and sometimes, if more rarely, without even reducing) fertility. I'm saying THAT IT ACTUALLY DOES HAPPEN, and that there are many observed examples of it happening.