Bill - what I was getting at was that (in my experience) atheists usually appeal to science and empiricism as the bedrock for their worldview, since these give concrete facts we can deal with (as opposed to an 'empirically unprovable' God). But in this instance the empirical facts point in the opposite direction to the world view of most atheists. They favour choice in the matter of abortion even when the empirical facts suggest that to do so is to favour murder in certain cases. From a rational and even human moral point of view, that seems difficult to sustain.