So if morals are relative, or situational based, then who defines when the situation is justified or not? The person making the decision? Or the society in which he/she is a member?
I think there are absolute morals, BUT, at a society level, not universal. Society's set expectations of what is considered 'normal' or 'abnormal'. For example, in many eastern societies, eating dog is no different than a chicken. But, for western societies, it is considered 'abnormal'.
I think the same thing applies to abortion. But, instead of the usual context of geography / race defining the societal norms, it tends to fall more along religious lines. After all if your faith subscribes to the idea of a soul imparted by your God at the time of conception, it is not acceptable behavior to abort. However, many western civilizations have weakened the influence of religion on societal norms, and thus abortion is legal and considered acceptable to a majority.
It think that is the root to why we may never see and end to the debate of abortion. To end the debate we must prove beyond a doubt of the existence of a soul. Some would argue that science has with the study of quantum physics string theory and the recent news of mathematically proving the existence of multiple dimensions.
http://blog.wired.com/wiredscience/2...-test-for.html
http://www.telegraph.co.uk/earth/mai.../sciuni121.xml
But I'm digressing....