Perhaps this is why they argue so about whether the “clump of cells” is a living human. That and possibly to absolve themselves of evil. I dunno.
Mostly, the latter.
Re the first part, point out to anyone who would listen (few) that a DNA comparison between mother and "clump of cells" would prove they are from separate human beings.
Not that they'll listen. Most pro-abortion people want to be a part of the in-crowd and does not want to be on the same side of an issue as the churches.
Yet if they found a single-celled oeganism on Phobos, they’d be screaming, “WE FOUND ALIEN LIFE!”