It says that God created us mind and body in our mother's womb. Why would you want to stop something from God. Sure it doesn't say in the bible that abortion is or is not a sin. But doesn't it have to. It says very clearly that we should not kill.
Life startes at conception.
If you don't believe me then use this example. Look at a fetus as a flower. Inside the womb the fetus grows and develops. At birth we see what has been developing for so long. Now if you see this plant growing into a beautiful flower, you know that the plant is living before the flower blomes, so why kill it.