One additional point.
I know it is hard to argue for an assertion, especially of a moral claim.
You choose to believe life is sacred from the moment of conception.
If someone doesn't accept that assertion, what is your recourse?
To a god that many other don't believe in?
For me, I try to plant these things in some sort of mathematical or natural soil. I don't merely think altruism is a nice thing. I see that it is valuable and efficient thing in nature and in game theory.
So I wonder - is there some similar reason to believe in the sanctity of human life from conception? Something that isn't divinely ordained. Maybe there is. But I don't have a bead on it.
In your shoes, I'd be curious to dig a bit deeper than my assumption that god wills it. I don't think the abortion question arises in the Bible - after all, if any book is filled with justified massacres, it is that thar book. But even if it does, does nature or philosophy confirm the value of sanctifying life somehow?
and if so, why not all life? - this would make you a jain.