> Is it going to become a fully formed human? Yes. Then it is human.

Are you really bringing this back to the moment of conception? Because there's no guaruntee that a fertilized egg is going to become a fully-formed human. There's just a better chance of it than that an unfertilized egg is going to become a fully-formed human. For that matter, every time you masturbate you're destroying millions of living cells that have a chance to become a fully-formed human. Where is the cut off point? 50%? 10%?

Consider the absurd results of treating an embryo as if it were a human:

We imprison pregnant women for reckless endangerment if they drink, smoke, go skydiving, bungee jumping or play a sport? The police have to investigate every miscarriage as a potential murder.

Once human cloning is worked out (and it will be eventually) you should never have a tumor removed or a boil lanced, because every cell in your body has the potential to become a full-fledged human being.

In vitro fertilization becomes immoral because it requires the production of many potentially viable embryos that aren't used.

The bottom line is that trying to treat a clump of cells that someday
might become a real human as if it has full rights leads to ridiculous situations.

And if an embryo isn't a human then birth control is as immoral as abortion. They both act to interfere with something that might in the future become a human being, but isn't yet. Again, it's just a matter of chance. If you use birth control you're taking away whatever chance there was for one of your sperm and her egg to eventually become a human.