It's problems lie elsewhere-- it's logic is just as good as the logic of your defense of the fetus' rights. It's logic was good enough to be a deciding issue in the law thru 400 years of witchburnings during the middle ages.
My point is that we should arrive at our laws through reasoning about things we understand fairly well and share fairly universally--they should not be derived from predicating them on inchoate feelings we might have the something may be taboo.
This is a bad idea with an terrible track record we have been trying to shake for 2000+ years.