I disagree - I wouldn’t consider a stem cell a separate human being, it’s a small part of the whole. Your skin is a part of you, but you are not your skin - you’re a collection of cells that compose you. Things get even more fun if we look at things from the Theseus’ Ship perspective, but that’s a different discussion. My point of contention is the dehumanisation of the fetus - it’s dishonest. It’s more honest to call it a human because it is in fact human, and given time, it would develop further into a child. That’s not the problem - the problem is whether we want that to happen, and at which point do we cross the line when it should no longer be permissible, if such a line exists. Some fanatics say that even a morning after is not permissible - that’s ridiculous, a fertilised egg has no chance at further development without nesting, even if it is human, and they’re often discarded by a woman’s body anyway. Not every fertilised egg gets to grow. On the flip side, fanatics on the other side are okay with abortion all the way up to 5 minutes before birth, when the child is fully formed. That’s equally ridiculous, and no different than infanticide. There’s a point between those two extremes that the lion’s share of society can agree on, it’s just a matter of finding that point. Scientifically speaking, the most agreeable point is before rapid brain development begins, as it’s hard to argue personhood with no brain. That’s the correct track, I think.