To me, abortion is a simple issue that should be resolved between the pregnant woman and her doctor. It should not be a legitimate issue in which other parties offer opinions or make decisions. The argument that is normally put up is "Someone should speak for the fetus". Well, the fetus, as a specific future personality, really isn't important, it being a result of chance. We are a direct product of our genes transmitted down through hundreds of generations. When one considers the wars, diseases, personal decisions, etc made down through the ages in which our ancestors were involved, the probability of a specific individual being born is vanishingly small. For example, all the bombs which killed individuals during WW2 were dropped without the intention of killing or saving any specific individual. The bombardier did not know anyone on the ground, his intention was to kill as many people as possible. The same thing can be said about the plagues of many diseases and so on. Billions of individuals were born, but no specific individual was planned from the beginning. If one claims that a specific individual was planned by God, then one has the very awkward question of "Why did He plan that certain innocent children be born severely handicapped, physically or mentally"? Surely, we are not going to blame Adam and Eve, are we?
If one can use the argument ".... for the greater good" for the war in Iraq, it can also be used for the support of abortion. The population of the earth is increasing at an alarming rate and over- population is a contributing factor for wars, increased disease, crime, hunger etc.
Almost all abortions involve the destruction of an innocent potential sentient being. This is a primary argument against abortion. Yet, almost all opponents of abortion agree to certain exceptions, including rape and incest. I have to ask "In what ways and manner is the innocence of an embryo created via rape/incest less important than an embryo created by other means"? This point illustrates that social customs, and not morality, are the basis for a society's position regarding abortion.