"Prenatal humans" and I have the same right to life before birth and that is determined by our human parents. After human parents have delivered someone into this human environment, then there is an obvious right to continue. That is my personal belief and I know it is different than yours. The problem here is that you assume to have moral authority superior to mine and therefore you believe that you may decide personal family matters for me. That is wrong and clearly rejected by the majority in this country.
It is often a problem to make absolute moral conclusions regarding human circumstances where information and understanding is incomplete. If you want to do that for your own family, fine; but don't assume that your limited-knowledge moral/religious judgements aught to dictate my family's personal reproductive decisions. The point is not that we want to choose abortion; the point is that it is our choice not yours.
My personal belief: God produces Life. God's life is perfect and eternal, spiritual.
Human parents produce human life. Human life is imperfect and mortal, material.
There is a clear difference here.
I apply "sanctity of life" to God's spiritual life. You apply it to prenatal human life. We have a religious disagreement. Since we value religious freedom, your particular religious belief will not dictate my personal reporductive decisions.
Note: While you will not be successful in making personal reproductive decisions for others, you may indeed help the democrats win elections. Making this personal decision a political issue has helped the democrats win many elections they would have lost otherwise (see California). This may not have been your intention but it is a fact. Keep pushing this contentious religious belief into the political arena and you will keep loosing elections.