(Let's REALLY tick some people off now ...)
To me, it's really simple -- There are consequences to your actions, and people need to take responsibility for their own actions. If you speed, you may get a ticket, you may get in a wreck, or it may cost you or someone else their life. But it's YOUR DECISION whether to drive responsibly or not, and you reap the consequences of your actions.
If you have sex, you may get an STD, or you may even get pregnant. If you do, it's your own fault. If you can't handle the responsibility of a child, then you're not mature enough (regardless of how old you are) to be fooling around with sex. Don't try to get out of your problem with an abortion. It's not a quick fix. Honestly, it'll just introduce a whole new array of problems, physically and emotionally. I don't know this first-hand, but I surely do second-hand.
Carrying a baby for nine months and giving birth to it is hard on the body and on your emotions, but a child is a blessing. If you can't handle raising a child, then let this child be a blessing to someone else. I know dozens of people who cannot have children and have chosen to adopt (and some who CAN have children that have adopted as well.)
Granted, this doesn't take into account rape victims. They're not responsible for what happens to them. But those are in the extreme minority of abortion cases. (And studies suggest that most rape victims don't want abortions anyway. One link on it is
http://www.afterabortion.org/PAR/V2/n1/RAPESUM.htm)