There is a thread dealing with a particular dilemma, but I wanted a more general thread, more about the morality of abortion rather than its legality.
I will start with my opinion which might be contraversial here.
For late term abortions I think the differences between the fetus and a new born child are to minute to justify an abortion in ordinary circumstances, as a utilitarian I would say that if the baby and the mother were to die, and only the mother could be saved, that abortion would be permissable, this applies to my views on early term abortion as well (see the rest of the post).
For early term abortions, it seems to me, that more consideration should be given to a developing fetus/embryo. Most of us wish not to be killed, it is because we wish want to continue living, experience the potential life we have not experienced. Therefore we must value potential life as much life that already exists.
I will deal with two objections (to the potential life argument):
1) One might object that potential life applies to sperm, egg and fertilized eggs that don't implant. I think this is true, but there is no way of preventing this. People might say that masturbation would be comparable to genocide if what I say is true, but so would intercourse, even if it ends in pregnancy. When Catholics say contraception is evil for this reason, they cannot be right, because every action, unprotected sex, sex, even abstinence leads to the loss of potential life.
2) Another objection goes like this: A boy is under 19 (in a country where it is illegal to buy alcohol under that age). To say that a fetus/embryo has a right to life just because it has a right to potential life, is like saying this boy has a right to buy alcohol because he has the potential right to do so. I think this objection fails because abortion is more like preventing the boy from turning 19, abortion prevents the embryo or fetus from ever fulfilling its potential right to life.
I'm probably going to get chewed out for this... but your thoughts are welcome.