It wasn't all that long ago that it was considered normal to send small children up chimneys, or to work in amogst lethally dangerous machinery in factories, and to beat them soundly for the slightest infraction. Now, thankfully, such things are unconscionable, at least for the relatively developed nations. So yes, moral standards can change, within a society as it matures and between coexisting societies.
At the age of five, Skagra decided emphatically that God did not exist. This revelation tends to make most people in the universe who have it react in one of two ways - with relief or with despair. Only Skagra responded to it by thinking, 'Wait a second. That means there's a situation vacant.'