I'm sort of beginning to think that Adam and Eve are Desmond and Penny.

Now that we know that Charles Widmore was on the island, I'm kind of thinking that Penny, Desmond, and little Charlie go to the island, Penny and Desmond are killed, and little Charlie ends up being Charles Widmore. This creates a paradox, though, but for anyone who's ever read "Rant" by Chuck Palahniuk, it makes sense.

So Penny would be her father's mother.