To respond Tac's comment about separating humans and apes via Turing test and being able to communicate. Apes(such as chimps) are in fact able to communicate with each other and to some degree, with humans. For example, it has been shown that apes can learn sign language(to some extent) or point pictures that make words(written language). In one situation, the chimp pointed out symbols for(or was it the sign language, I can't remember for sure) rice and sauce when the caretaker gave it some rice to eat. From this, the caretaker understood that the chimp wanted to have some soy sauce with it's rice, as the caretaker had forgotten to add it to the meal(the rice was usually served with soy sauce, so the chimp pointed out that the sauce was missing).

So, the apes are capable of thinking and communicating(apes are not capable of speech due to the structure of their mouth, but such should not be the defining factor, as there are mute humans too, who can clearly be judged sentient), even though they are not of our species nor are they as intelligent as we are. Also, I'd like to point out that Turing test has been made for testing intelligence of computers programs, so its suitability for judging intelligence of human being is questionable. Computer programs do not have an infant stage and judging infant humans by the standards set to computer programs is plain ridiculous. An infant is not human because it does not know things right now? Quite frankly, that's just ####. Where exactly should the line be drawn for abortion I'm not quite sure about, but the kid is sentient enough by the time of birth. I'd probably draw the line somewhere between fetus and embryo.