Personhood

Some interesting ideas have been raised by the movie on Koko and the introduction of Donna Haraway. Apes (especially cases like Koko) and cyborgs (ie. OncoMouse) are considered border cases by Haraway. She suggests that we should extend personhood to apes and cyborgs. However, I see a possible slippery slope problem. If we extend personhood, where do we stop. Should dogs and cats also get personhood? Also, I think there is a difference between apes and cyborgs. Apes seem as if they would be restricted in their intelligence, whereas cyborgs seem to be able to be upgraded when needed.