I'm not a big abortion blogger. It seems most people view abortion in terms of black and white. It's either akin to slaughtering babies, or it's a key aspect of woman's rights. And since the arguments seem to devolve into these simplistic terms rather quickly (even more so than in most political arguments), I remain confused.
One important question in this debate is when life begins. Pro-lifers have a very simple answer: at conception. Pro-choicers have a bevy of objections to this. Some are pragmatic (""If a fire breaks out in a fertility clinic and you can only save a petri dish with five blastulae or a two-year old child, which do you save if all are equally persons?"). Others are theoretical--it is fair to argue that even if life begins biologically at conception, one does not have moral personhood until some later part of development (incidentally, the Catholic Church used to abide by this through the doctrine of "ensoulment", which did not happen "at conception" but (I believe) two months into pregnancy. But I digress). Peter Singer essentially believes this--he says that a fertilized egg is unquestionably alive, and unquestionably part of homo sapiens, so its a bit peculiar to say its not a "living human." He continues to argue that something else besides being biologically alive is required before one has complete human rights. Unfortunately, Professor Singer also defends infanticide, a position most pro-choice people would rather disassociate themselves from. On the flip side, some people say that it is illogical to assert even "biological life" begins at conception. PZ Myers takes this view, arguing that the privileging of fertilization over other stages of fetal (and human) development is completely arbitrary.
Thus, I'll group the objections to the "life begins at conception" (LBAC) claim in the following categories: it's (a) practically untenable, (b) based on falsely replacing moral personhood with biological personhood, and/or (c) biologically arbitrary.
All fair objections, and I find them compelling. But we still need to answer the question: when does life begin--if for no other reason than we think killing "people" is generally bad, so we need to establish who "people" are so we can avoid killing them. If one believes that "In a free society a woman would be able to terminate with absolute ease an unwanted pregnancy for any reason that strikes her fancy" (and I realize that not all self-identified "pro-choice" people sign on to that statement), then one needs to create a definition of life that precludes a fetus at any stage from being included. Because if a fetus is a full human (or at least as fully human as an infant) at any point in its development, then abortion "for any reason" becomes morally untenable. So I give an open question to pro-choice bloggers out there: when does life begin?
The answer should avoid the objections that are lodged against LBAC if it's going to be valid. One can object to LBAC on any or all of these grounds, but to be even-handed one kind of has to make sure one's own definition doesn't fall into the same trap. If the only objection is practicality, then why wouldn't "life begins at viability" be a valid response (which would sanction many abortions)? That seems practical in most cases, and while there are cases where it runs into trouble (life of the mother, for example), that problem also manifests itself in certain cases with post-natal children (a child with a severe medical deficiency born to a family with no health insurance bankrupting them). If the objection is based on "moral personhood", then when does one receive moral personhood--and will that definition also sanction killing newborns and/or the severely disabled (or even the elderly)? If the objection is based on biological arbitrariness, then explain why your standard is less biologically arbitrary than conception.
Again, I'm not taking a position as to any of these. As I pointed out, LBAC has serious flaws that I think preclude it from being a sensible standard for the abortion debate. But I do think it is valuable to explicate when full human life begins if not at conception. So have at it, pro-choicers--my comment boards (and/or trackbacks, if that's what you prefer) are yours.
UPDATE: A brief clarification, because I think I'm being misunderstood. Several people have said that the important question is not when life begins, but when we begin to protect life. In other words, the claim that moral personhood, not biological personhood, is the kicker question. That's lovely--I'd be inclined to agree with it myself. But that just shifts the question back a notch--when does moral personhood begin? If that's the position you take, then that's the question you have to answer, in lieu of "when does life begin," because I suspect the pro-lifers would argue that moral personhood is endowed at the same moment biological personhood is--I.E., at conception.