By the way, I'm not sure if anyone recalls this, but killing a pregnant woman yields two murders.
I am not sure if that counts ONLY if the baby is in a stage in which it can perform some action, I haven't exactly seen a case in when the person who died was, for example, two weeks pregnant, but then again they aren't very specific when announced.
But it doesn't have one yet, it certainly will eventually, just as babies aren't really capable of sentient, cognitive thought for year after birth. It doesn't mean the baby is less human because it's less developed, it just means it's just that, less developed.
So, if I purposely kill sperm cells, I am killing a baby because it is a baby that is technically "less developed"?