I see what you're saying, man. But that's the question, I'm asking you at what stage do we consider it to be a person? The term life is nebulous at best (in the early stages).
No, it's not nebulous. It's as close as you can get to a universal scientific consensus. Life starts at conception.
The sperm and egg cells before conception aren't alive?
They are, but they aren't a human life.
The whole "life" argument has always been a stupid one, promulgated only by dimmest of the dim, like Blobby Necrobrain. The question isn't and has never been about life, but about what makes a human. Some call it the soul, though I object to that on pragmatic grounds -- it's not really definable, even within the context of a specific religion. But all the more objective definitions are equally amorphous. Birth? Too late, by nearly anyone's defintion. Heartbeat? Irrelevant. Viability? That's a moving target, and most people object to just randomly killing disabled elderly, comatose, or even unconscious people, so it's a crap definition. X weeks? That's purely arbitrary. You can go through the rest of the list, and they're all garbage.
That's why people fall back on conception, because it's the one clear, hard line in the entire mess. Even if people don't agree that two cells makes a human, as long as they fall on the less permissive side, it's a place to rally around.
The alternative is to admit it's fuzzy, and start with most people's intuition, and derive some guidelines backwards. Most people seem to agree that if a baby is viable, killing it is clearly wrong. Since the earliest preemie to survive is around 19 weeks, that's a start.
The other consideration is relative harm and responsibility. Who suffers more, if the line is drawn in the wrong place? The mother, or the baby? Clearly, the baby. Because the mother was an active participant, had many decision points, and giving birth, while not risk-free, isn't guaranteed death. Which abortion is, to the baby. So based on the degree of relative harm and responsibility, there's a strong argument for making an error in the direction that inconveniences the mother, rather than killing the baby.
The final consideration is enforcement. We have to rely on the proxy of the government to make these calls, and do we really want that? I sure as hell don't. The politicians on both sides are some of the worst humans beings who ever existed. That's a strong argument in favor of removing legal barriers entirely, but using soft measures to encourage certain decisions. Wait times, education into alternatives, pressure using social mores, that kind of thing.