I'm also in the camp that's not focused on the retributive aspect of punishment; I'm not disputing that its main purpose is for the good of others. My argument is that the people being punished in this way have in some sense forfeited part of their right not to have their autonomy violated, by demonstrating inability to stick to a social contract that has been agreed on as reasonable. Views can differ on whether that's reasonable or not, but it's firmly distinguishable from someone forfeiting their autonomy because they got pregnant.
I don't agree that financial wealth is "just" labour in another form. Of course that's true in a sense, but the difference in form is an important one. I guess I can appreciate that others might not agree with that --- but I still don't see that that puts them in opposition to abortion. Society tries to minimise the extent to which one's bodily autonomy is limited to by the need to earn financial wealth --- for instance, I think we can agree that slavery, debt slavery, debtor prisons and workhouses are Bad Things. So under this view of autonomy, abortion belongs in the same category.
My argument is that the people being punished in this way have in some sense forfeited part of their right not to have their autonomy violated, by demonstrating inability to stick to a social contract that has been agreed on as reasonable. Views can differ on whether that's reasonable or not, but it's firmly distinguishable from someone forfeiting their autonomy because they got pregnant.
I don't see why you would elevate the social contract in any extreme way like that; you mean abortion is OK, and execution not OK, solely because the latter is imposed ...
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.