I think the responses so far ignore the social implications of this debate, which I think have been the ultimate determining factor...at least politically. Before I can agree to believe that abortion should be illegal, I would like to know what business the government has in telling a woman what to do with her body, which the fetus relies on for survival?
Most importantly, I think it's important to point out that the scientific "evidence" displayed so far is not really evidence for either side at all. What is being used as "evidence" are the interpretations about what these results mean and how we should react as a society. There no ultimate logic or reason that can successfully bridge the gap between the moral absolutism of "pro-life" and the scientific evidence presented. It's all in how one interprets (a) the evidence and arguments and (b) how we as a community feel we should react to this interpretation. To me the reliance on personal interpretation and emotion suggests that moral absolutism is probably a disposable position. This debate has been reduced to a matter of one's interpretation of the means and goals of society. That being the case HERE, what grounds do we have for telling someone what they can do HERE? The absence of something self-evident in this debate is exactly why abortion cannot be considered anything but just that...a matter of opinion - choice.
To conclude, I'd like to throw in two more criticisms of the "pro-life" argument. One, they contain certain theistic assumptions, the most obvious of which pertains to the sacred nature of human life, which certainly lacks jusitifcation. It also contains the anthropocentric assumption that human life is superior to other life forms that we kill which, again, no matter what you believe, is not justified.
A restriction on freedom requires sound logic, at the very least. Unless there is some imperative argument requiring abortion to be treated as murder (and i cannot think of one), then I'm not sure there's an imperative to restirct a woman's right to exercise her freedom...especially over her own body. Does the government have the right to dictate what happens in the womb? I'm not in favour, given the arguments so far.
Jon