You should note that you have the luxury to even consider the issue of abortion because you've already been born.
Just because there is a selection bias doesn't mean that the bias results in specifically positive or negative outcome. I could argue that because you were born you are against abortion because you were born too, and my argument would be just as valid. Of course I'm not making that argument, because it is just as silly as the one you are making.
If Bach had not been born, one of his brothers would be the composer?... Same for Einstein?
> If Bach had not been born, one of his brothers would be the composer?... Same for Einstein?
What if we had aborted Hitler? Or Stalin? Or John Wayne Gacy?
Actions have to be judged based on the information available at the time, not on what might be learned decades later.