Now you are going from sublime to ridiculous. I have a 16ga. shotgun waiting to terminate your life if you enter my domain, and it would be perfectly legal in Alabama to do so. It doesn't change the fact that a would-be intruder is human! Maybe you don't like that, maybe it's not something that should be the case, but that is the facts of life and the law, and thus, a thing we call "REALITY!"
I have no idea how you think this is applicable to your point. I have no right to trespass on your property or person but a zygote does? Okay, whatever...
I am human because I have the capacity to live as a human. When I lose that capacity I am no longer alive as a human. And the zygote that does not develop that capacity is not alive as a human and was never alive as a human.