Morality is shaped by the culture that one exists in; most often reflecting the ideals of the region where they are born.
Who decides what morality is?
Morality as a word can refer to one or both of two different things:
1) principles concerning the distinction between right and wrong or good and bad behavior. and
2) the extent to which an action is right or wrong.
As The Z says, "Morality is shaped by the culture that one exists in; most often reflecting the ideals of the region where they are born."
And it is good if the ideas of the region are reflective of principles derived from a proper consideration of the nature of man and what he should do because of what he is.
Prior to acting, we have to choose what is moral, but it must be an informed choice. "Conscience" is the last act of the practical intellect before we do something.
And it can be argued that we are only able to choose what we see as "good."
So it is important to have our principles at hand when we are deciding what we should do in a given situation.
There is Objective Morality which is based ,in part, by those things in the culture you belong to which are considered good or bad.
I feel Morality (in General) was a necessity for a society, such as ours, to thrive. We needed to be cohesive to survive, and both Empathy and Reciprocity were ingrained in pack animals so that the group could work together toward common goals.