Despite my reluctance to enter into these dicey subjects, I will weigh in with personal experience as it related to this topic:
By the time I was born in 1960, my mother had been suffering from severe mental illness for a long time (diagnosed as psychosis back then). She also was highly anorexic (before they knew much about treating this problem.) She spent much of her pregnancy at the Mayo Clinic, and due to her precarious health, she was encouraged by her doctors to have an abortion, which she, for her own reasons, refused to do. She weighed 80 pounds when I was born (at normal birth weight, by the way). This wasn't a rosy time, however. I never bonded with my mom, who was too out of it mentally to do so, and I was pretty much passed around to various nurses, etc. Unfortunately, my mom's illness forced her to get violent toward me as an infant--my dad had to rush me to the emergency room on one occasion--and everyone realized I couldn't be left alone with her. In her own demented way at the time, she wanted to kill me. So, I was sent through the gauntlet of various caretakers. Thankfully, when I was two and my parents divorced, I went to live with another, very stable family which probably saved my life and gave me a very happy childhood.
Now, I've had my share of difficulties because of this early background, no doubt about it. But I bring this up just to point out that even good candidates to be aborted because of external factors(and I was certainly one) might just beat the odds placed against them. Despite all the odds, I managed to come out with a genius IQ, and my own emotional struggles have in later years led me to become pleasantly eccentric. My own son and I have a great time hanging out together. Point is, life's been a blessing even in the hardship. Even my mom is doing much better than those many years ago and is enjoying life, though she won't ever be quite "normal."
So, my purpose as far as the abortion debate is concerned is simply to state that when that tragic decision is made, one isn't just aborting what is, but also what is to come. Our human life is a continuum, and though a tiny fetus isn't the equivalent yet of a developed individual (at least at some levels), it is already in process to become that. I think that's the greater pity of it, and the part of the equation that is typically ignored.
Now don't get me wrong. I'm certainly sympathetic to women who are so desperate as to find even abortion expedient. The greater pity, though, is that choices are made with permanenet results based only on the here and now, which is indeed a very limited picture of things and probably of limited value in judging the worth of such a decision. The fact is, life is dynamic with respect to time: things change, we have hardships and get through, and people are different than they were half a lifetime ago. This is the more clear picture, and it's a pity that we can't look into the future and see it all before making such a fateful decision.
You see, it's kind of scary when I think that my life might not have happened at all. In fact, it was encouraged by the medical authorities not to, and it certainly met the criteria for being justifiably ended, even at a time when abortion on demand wasn't legal. Of course, that would have extinguished every shred of being and experience that's made me me for almost 45 years. Now, do I believe that all that my life has been should be expendable based on my mom's inordinately severe difficulties at the time of my birth? I think that's the real question.
It's all this kind of longitudinal thinking that I can't seem to help doing that leads me to dispute the claim to an innate and inalienable "right" to abortion. Yes, certainly it is a legal right, but I don't believe it is a human one. It is, rather, an exercise of decision and power in a moment of difficult circumstance--one that ends all that will be of one life in order to spare the condition, quality, and at times even the viability of another life. In the end, it is indeed a choice, and a choice that changes the world.
So, does this mean abortion shouldn't ever happen? Probably not, since life can be truly horrific and fragile, and even tragic expediencies seem needed in unusual circumstances. Even Jesus granted the expediency of divorce under the right conditions. But such expediencies were meant, I believe, to be there as a safety net when all else in life has failed. For me, the tragedy of abortion is not that it occurs, but that it occurs frequently and often with little more than the painful circumstances of the moment used to make a decision that cannot be undone when said circumstances have changed. In the end, perhaps what distinguishes us as human is that we bear responsibiilty for the choices we make, come what will. It makes me look fondly at the placid life my cat leads.