.... The original sin had nothing to do with sex. The original sin was from the temptation of wanting to be like gods by eating the fruit. Sex had nothing to do with it ... well ... unless you're talking about that movie ...
Now if the Original Sin in this game is the desire to be 'Like God', then it all becomes relevant. ....
Where does this idea spout from, interesting concept..but I don't quite understand the connection. Having Original Sin is not god-like, but very mortal. It is one, of many, things that separates us from being gods(according to religious interpretation.)
From wiki ' Adam is recognized by some as having brought death into the world by eating the forbidden fruit. Because of his sin, his descendants will live a mortal life, which will end in death of their bodies'
So it seems to be the opposite, so one could say because we are not god-like, we must work hand-in-hand(ie the game cover) to overcome our defects as mortals.
daft73 covers it, but it is from the Bible. They desired the fruit as it would allow them to know the difference between good and evil, thus making them like God in that aspect. Obviously that did't work out like they thought it would.
Again, if this game is about the basis of a man or men, who do something to 'be like a god', then the game name becomes relevant to the biblical original sin.
Sex between Adam and Eve, before or after the fall of man, was never sinful as they were in fact "made for each other" and it was always the intent that they would reproduce.