Because it's not killing a living being. It's a glob of cells with no brain, no heart, no human organs at all. The amoeba on your bathroom floor have about the equivalent status of development at this point. Granted, I could see your complaint if it was, like, late-third-trimester abortion. But likely, it's not.
Arctic seals = living, sentient beings that are important to an entire ecosystem.
Globlet of nonconscious cells = not a living, sentient being in any term of the word.
On another note, do you eat meat? Do you support the Iraq war? Then you're not at all pro-life. You know why? Because eating meat means you're killing animals, and animals... are alive. Soldiers and civilian people routinely get killed in wars... and they're alive. You're a bloody poser if you say you're "pro-life" and are then SELECTIVE about which kinds of life you support.
If you are, in fact, "pro-life," then you have to be a vegan, too, and anti-war, and you also have to stop cleaning your bathrooms, too, because those germs are living things, too, and no more swatting flies, because those are alive, too.
I hate the term "pro-life," if you haven't noticed. More appropriate term? "Anti-choice."
