Lyric discussion by grokslaw 

gnskov is correct that this song probably refers to the story of Cain and Abel in the Old Testament as a slightly incorrect reference to "original sin." Supposedly Cain had a mark put on him and his children for killing his brother Abel pretty soon after Adam and Eve got out of the Garden of Eden.

It's the first murder in the bible and some religions claim that the "Mark of Cain" was a dark skin that Cain and all his descendants were cursed with. They used this story to discriminate against certain people because of their skin color and put laws in place against interracial marriage and other things. Basically, using the bible as an excuse for their own discrimination and bigotry.

I forgot what a good song this was until I heard it again recently.

Although actually "Original Sin" means something different in Christian Theology. (It means that everyone is sent to hell unless baptised since they inherit Adam's sin automatically, no matter what.)

All this Christian theology/mythology is BS, IMO, but this song points out that people should be treated equally and that interracial relationships shouldn't be a big thing.

An error occured.