Why if you cause an accident are you not responsible for a person's death but if you accidentally get pregnant are you responsible for the new life?
Because it's a death, regardless of who was responsible or suffered because of it, it's an end of something.
Pregnancy, accidental or not, is not an ending, it's the beginning of a new life that will suffer if it's creators don't do everything in they're power to prevent that suffering, even if it means they'll never see that life after it's delivered into this world.
Contrary to what a lot of you think, I'm not some heartless creep who spouts homilies and truisms, my concern over the abortion issue is that abortion wouldn't be an issue if people, all people, were well educated about reproductive health. A well designed comprehensive health course would include both abstinence and more secular methods of birth control, as well as educate the students as to the reasoning behind BOTH. However most parents in the USA are very uncomfortable with the idea of they're child as a sexual being. My dad, who walked my sister down the aisle to the man she sleeps with I would assume frequently, refuses to accept that she's an adult, she will always be his baby girl. The main problem with Sex Health, is that you can't say we'll have it for them when they're all 13 years old. Some people mature early, some later. I went to school with a girl that looked like she was 9 or 10 until sophomore year, she came back from that summer and no one recognized her.
My point is that there is no one-size-fits-all approach to this issue. It's a touchy subject when a large portion of the populace won't even admit in public that a marriage is as much a sexual relationship as it is spiritual.