Brainstorm

[Excited Penguin]

At the moment of conception it is, biologically, a human entity. I don't know of any other fair way to define that point other than by what it actually is. It would just be arbitrary otherwise, and when it comes to defining another being's humanity, history has shown us that being arbitrary on this can lead to horrific things. (think holocaust, slavery, the slaughtering of indians in the new world, etc... all in the name that these people weren't actually "human")

But why at the moment of conception? Do we consider a sperm quasi-human, prior to this?

I think we should consider whether it can suffer and maybe think(or be self-aware) in any way before we actually define it as a person and consider it with the same dignity we consider other humans. Otherwise we are merely talking about its potential to become a human being.