I don't mean to be facetious here, but babies don't just pop out of nowhere. They have to be conceived through sexual intercourse (generally). Not having unprotected sex is the moral high ground, not abortion. Let's not get into that sticky topic as it's a corner case (rape, etc).

I'm not so sure that that is the sole reason they get touchy about the topic. I think somehow people view having children as some sort of inherent "right" of being a human. Sure, of course no one should stop them from doing it. All I'm saying is that it's not very moral or virtuous to bring a child into this world that you can't reasonably take care of till adulthood.