Now there you go. You said everyone knows, but I didn't know. I have always believed without ever examining any scientific evidence. In fact I do not think 'everyone' knows. Did you just use your own argumentum ad populum?
We are getting distracted from my original point which was that an abortion is a sin. One has to believe in *** (which I do) to believe there is such a thing as sin and, therefore, morality. I do not think one can understand why abortion is so heinous unless they have a moral baseline. I do not know whether you think murder is okay or not (and here I am referencing all forms of unjust life-taking, not just abortion). If you do think murder is wrong, what do you base that on?