Building upon what the others said, especially Quesi, if abortion is wrong because a potential human being is disposed of, then not being pregnant is also wrong, because a potential human is not being conceived. If abortion is wrong, every single woman of childbearing age should either be pregnant or nursing or trying to get pregnant, 24 hours a day, because nothing else is excusable. Oh, and all this needs to be done despite sex being a big sin, because we wouldn't want to modify any old, outdated moral standards just to make creating children a little easier. Which means that all women, once they hit child-bearing age (you know, around 12) should be having sinful sex all the time and then spend their pregnancy atoning for their sins. That is what god wants, I'm sure.
I personally wish that nobody ever had to have an abortion. That every child conceived was wanted and that the parents were able to care for it. I wish that we could create a world where the subject never had to come up because all the reasons for abortion had been eliminated. But as long as we concentrate on the outcomes instead of the symptoms, as long as we complain about what is happening instead of creating different circumstances and actually fixing some of the problems that lead to abortion, we will continue to have this debate.
In the United States, having a normal, healthy baby in a hospital, with an overnight stay and the delivery, etc. costs something in the region of $16-$18,000 dollars. I base this on what it cost my niece to have a baby two years ago. That is 1/2 of what the average American makes in a year. Yes, some folks are fortunate and have health insurance to cover these costs, but not all do. I have a cousin who had three children, none covered by health insurance, because she couldn't get it. She had breast cancer as a teen and could never get insurance because of pre-existing conditions. Fortunately she and her husband had good enough incomes to allow her to have those kids, but not everyone is that lucky.
Pay attention to the "why's" of the issue. Don't concentrate on the outcome, because an aborted fetus looks the same to you no matter the reason for the procedure. If you don't like that it is happening, do something in this world that makes it a better place that offers more alternatives to pregnant women than just continuing poverty, abuse, uninsurability or bleak futures.
The actual importance of the abortion issue, as outlined by the religious right, is that it helps divide. It helps define how that particular religious denomination differs from others, especially the non-religious. Division is important to religion. So important that it rhymes. The "I'm better than you and here are some of the reasons" mentality of religion, be it over abortion or gays or school prayer or anything else is all part of the game. Hence actually fixing things like the reasons for abortion is low on religions list of to-do's.
When two or more religions agree on any given issue, like abortion, they find other reasons to dislike each other, albeit it more privately. Baptists and the Church of England can walk hand-in-hand on the issue of abortion, but if those two denominations finally got rid of everyone else, then they would start shooting each other, because division is important to religion. And once the world gets down to one religion, the adherents will start finding reasons to hate each other over different interpretations of biblical verses, because division will continue to be important.
The last believer will win. And die. And find that there is no heaven after all.