PROVE IT. I
wrote this specifically to point out the idiocy that is typically blathered in association with the words "human life". But even without referencing that somewhat lengthy document, I can point out that if you call a zygote "a human being" then you are causing trouble for yourself. That's because a zygote can become a morula, which you would also call "a human being". And then a morula can become a blastocyst, which you would also call "a human being". But next, sometimes a blastocyst Naturally becomes a normal embryo, and sometimes it Naturally becomes a hydatidiform mole --and not even the most vehement of abortion opponents will call a hydatidiform mole "a human being". THEREFORE, just because it didn't grow like you assumed it might, when you call the zygote "a human being",
you are now forced to say that a human being, through perfectly Natural growth, can become a human non-being! It is much more rational to say that a zygote is a human non-being, and that the developing human remains a non-being until it actually, legitimately, qualifies for the label of "a being" (still of the "human" type).