i think i relate sin to intention. you could innocently engage in immorality by just being true to yourself, to your desires and your drives, without necessarily having malicious or harmful intent but you couldn't sin in all innocence... well, maybe you can, i wouldn't put it past you, lol! (((OURScott)))
but, yes, the concept of sin is definitely religious and personal, whereas morality is applicable in any social group, what is considered sin in one culture, may be totally acceptable in another but what is considered moral is now becoming a secular concept because it is a term that is starting to expand through being informed by that which is valid for all - science. although, thinking about it, both carry with them certain assumptions and require prior knowledge, as well as a degree of commitment to the accepted standard. oh gosh, i'm getting outta here before i become irretrievably entangled in my own semantic labyrinth!