Ahhh abortion. I apologize in advance if I overlap on material because I haven't had the time to read the rest of the thread in much detail.
This is one of the more interesting discussions because I can empathize with both sides. "Pro-life" is probably one of the only social conservative stances that I can understand and see why they'd adopt their stance.
That said, I would say I'm "pro-choice". I feel abortion should be an option, though if I were ever in such a situation I would take a long time to think about it, and I don't think I would get an abortion... but then, it wouldn't be me that would carry the baby.
I haven't read the thread in depth but I can guess that the differences in pro-life and pro-choice lies in the premise of when a human being is considered to exist. Some will say birth, some will say conception, and many will cite a time somewhere in between when they believe that the foetus is developed enough to be considered a human. I'd say it's difficult to say, because it would ultimately be quite arbitrary. What we do know is that the development of a baby during the 9 months is fairly analogous to recent evolutionary paths, in that we start out very similar to unicellular organisms, and then to primitive chordates, and then to more developed chordates, and then to primates, and then to humans. A chimpanzee, dolphin, or squid would ultimately be far more intelligent and subject to pain and emotional trauma than a baby let alone any stage along the way, but we don't have too much problem with killing squids or any other species (not that I'm alright with that either). It's an arbitrary placement of a blastula of a human above the blastula of any other species.
At this point, the difference will be made that, the blastula of a human can be put higher because it has the potential to become a human. Potential can be a fairly scary concept though, because an abortion also potentially leads to the loss of hundreds of people that would have descended from that individual. Still, the level of potential considered is rather arbitrary because I can look at all the wasted sperm ejaculated and all the wasted eggs menstruated and see all the different individuals that could have been great or terrible.
In the end, some sort of arbitrary moral stance is taken on both sides, and it's easy to accuse either side of being immoral. Pragmatically speaking, abortion has a lot of benefit in population control and fighting overcrowding. In utilitarian terms, would humanity be better off if we allowed all the babies that were aborted to exist? Would we be able to care for them as well as we can for the ones we have now? Or would overpopulation create great scarcity in resources that result in a general downgrade in standard of living?
I'm going to read the thread and see what else I can find. I'm very open to persuasion on this topic, because my opinion isn't fully formed.