Plus, the option of adoption is there.
That's just my two cents.
When you get older, you're going to want to have sex. That's a fair arguement if you didn't use any protection but if you did and it failes from the small % chance then your point is moot, as you're doing the most humanly possible to have safe sex.
Even so, i'm all for pro womans choice, if a 16 year old girl firetrucks every guy in a school unprotected and just happens to get pregnant than she should still have the option to get an abortion. In my eyes the fetus is not alive and she is doing the world a favour by getting rid of a child she isn't prepared to care for. A part of nature is avoiding having offspring you can't take care of, kangaroos don't mate in severe drought and lambs are born in spring, why? To avoid giving birth when it's not sustainable. Of course animals mate purely for reproduction whilst we do it for pleasure, so we have a lot more need for abortions if raising a child is not a viable option.
I'm also of the view that by not having children you can't care for you're doing society and the planet a big favour, too many people is really going to put strain on resources in the future. Of course I don't think that everyone should stop having kids but there should be restrictions or penalties for having too many kids, especially if you can't afford them, and abortions should always be available
EDIT: Even if you're fully capable of caring a child it's still in my eyes the parents choice as to whether they want to go through with it. Also I don't see abortion as playing god but rather being in charge of your own life (I don't consider the fetus a life yet)