This is an interesting question. Morality and ethics are 2 different things. Morality is the set of behavioral rules that society agrees upon, usually (but not always) based on religion (and all religions have a moral code of sorts). There's also morality that is dictated by the state or individuals in charge, which at times can be totally arbitrary.
Morality also tends to set itself up as "this IS right" or "this IS wrong".
Ethics on the other hand is the philosophy behind the principle. If murder IS wrong (morality) then is killing in self defense wrong (ethics)?
I think the vast majority of morality comes from society. In our society you have the hypocrisy of deciding the worth of life and death. If a doctor harms the fetus, its murder but if you decide to kill the fetus it's fine.
In the past, killing a baby after birth for even basic defects including low weight, was totally acceptable.
In other societies having same-sex sex was totally fine and in some cases expected, in our society many view it as wrong period.
Be it the US, Western Civilization vs East, modern Europe or ancient Greece, all morals change and are changeable based upon the whims of a society.
In my mind morality shouldn't be based on what we believe but based on what we know, as in science.
At least by using reason and science many things can be solved universally, not all, but many. And silly issues like sexuality, personal lives of people who are biologically adult (as opposed to arbitrary legal numbers), certain drugs, and so forth, it solves the question.
You also have the morality of the self. If I could have survived with no interaction with humans, what would my behavior be like? I would most likely hit the one who offends me, steal when I'm hungry, and shag anyone I wanted. Having a set of rules that protects the group is really important but how we come to those rules is what causes most of the problems.
