I think the last part of the dialogue is unconvincing: the Apologist weasels away from addressing the slippery slope argument. He seems to be saying that children aren't "human" until sometime after puberty--when they can "act all the acts, think all the thoughts, and feel all the feelings people can." The obvious response for the Contrarian is to ask whether the Apologist is opposed to infanticide, and if so, exactly where he draws the bright line between infanticide and abortion.
Fair enough. I already alluded to it and wanted to present my own novel slippery slope argument using parthenogenesis, but I guess it was a loose end.
I've added a little ordinary enough description of infanticide and acceptance. (Only really interesting thing is the Malthusian material.) The new material is at the bottom roughly where you'd expect it.
A few years ago, I wrote a little dialogue I imagined between 2 materialists, one of whom was for and one against abortion, centering on the personal identity question. I recently cleaned it up and added a number of references for the biological claims.
You can read it at An Abortion Dialogue.
Early feedback from #lesswrong is that it's a 'nicely enjoyable read' and 'quite good'. I hope everyone likes it, even if it doesn't exactly break new philosophical ground.