I guess if anyone could actually be considered "pro-abortion," it would be me. I've always thought discussions around the development stage of the fetus and whether it was a human being were irrelevant. Even if it's reading a book in there, it's still up to the woman whether it continues or not as far as I'm concerned.
I saw this argument recently and I thought it was a good one, including some points similar to those raised by JP above:
abortion discussion.jpg