Why does not human = pet? And, more worryingly, why would you want a pet human? Bestiality is illegal you know, thus, if they aren't human, you wouldn't be able to have them as some sort of sex pet. Which is the only reason I can see for wanting a pet human, other than "lulz this is awesome."
And, furthermore, why does it matter if someone can be percieved as "human" or not? In the past, someone once tried to seperate "humans" into species. He called the pure ones "ayerians" (possibly spelt wrong) and purged all the impure ones. If you start calling certain people not human, despite whether it is true or not, it
will lead to discrimination or worse.
Oh, and the whole "they have more chromosones" argument is absolutely utter bullshizzle. Seriously.
We have the same amount of chromosones as a potato. And as far as I am aware, I don't make good chips