A fetus and sperm are two completely different things. Also, I see where you're getting at but you also need an egg for a baby, so sperm by itself is useless anyway.
Also, I think people have a right to chose. I'd prefer if you didn't, but people have free will.
I define living as having biological activity. A rock does not have biological activity happening in itself. A plant does. It performs photosynthesis, the cells reproduce, etc. This does not happen in a fetus until around the third week, when the heart develops. If you are to get an abortion, at least do it before the heart or brain develops.