Well, the fact that her mom was pro-choice and the fact that she is, in fact, holding up her "little sign", proves that your bumper sticker doesn't have its facts straight.
You seem to be confused about what "pro-choice" means exactly. It doesn't mean pro-abortion, it means exactly what it says: Pro-CHOICE.
And what you didn't seem to get is that the woman holding up the sign was trying to tell you that her mom CHOSE to give birth to her, because she's pro-CHOICE. Get it?
Now you can mince semantics all you want, but that doesn't change the fact that people who are pro-choice want nothing more than the freedom to choose, and that includes the choice to have as many babies as they want to have. I am pro-choice, despite the fact that I couldn't even fathom having an abortion.
I'm not trying to change your convictions. But you should at least understand what your opponents' convictions are, if you're going to make an intelligent argument against them. Otherwise, you end up looking like a misguided bumper sticker.
However, your thinking here is even more flawed:
"CHOICE" is just shorthand for "pro-the-choice-to-kill-a-baby." It's easier to hide behind words than actually admit what you're doing when you're talking about child murder. And it's an old tactic.....Abortion became "choice" just as genocide of the Jews became the "final solution." It just sounds so much better.
BTW, the doctor that coined the phrase, "pro-choice" and presided over 60,000 abortions is now pro-life. Here's his story.
It's a bumper sticker for God's sake not a philosphical thesis. The point it makes is fair (and funny) enough even if it isn't an entirely water-tight argument.