Time for me to stick my head up and voice my opinion, I suppose
I'm not opposed to abortion - under certain circumstances. I think that as a manner of birth control it should not be an option. In cases of rape, incest, molestation, etc I think it should be offered, not forced. In the case that OnMyWay proposed, I think that abortion is validated. The mother to "give the greatest sacrifice"? What if the mother is single? Then the baby has even less of a chance of a decent life, becoming an orphan, and taking the chance of getting put in a very abusive home - personally, were that me (as the baby, not as the mother), I would prefer her to have an abortion and be able to complete her own life rather than leaving all of those uncertainties up to...well...chance.
Of course, I'm also for population control and was (in the past) a member of Zero Population Growth. There are enough great kids out there that need homes - how about adopting kids instead of having your own? Of course - I'm rambling and off topic now...sorry...
Abortion becomes murder (IMO) when there's a heartbeat. If it's in violent abuse cases (as mentioned above) I think it should be a valid option. If it's some 18 year old that wasn't being careful, I don't think it should be an option at all. Or perhaps, one abortion (one mistake) and that's it...
Of course, these are all just my opinions