College Humor has a new video that asks, "what if Marty McFly had sex with his mom in Back to the Future?" It takes the creepiness of Lorraine's attraction to her son to a new level, but it also raises the Oedipal themes of the classic movie above and beyond subtext. But the video doesn't stop at incest. There's also an exploration of the oft-posed hypothetical, "if you could have sex with yourself, would you?" The question is dealt with by way of a threesome involving Marty, his mom, and another Marty.
Because you know you wondered during Back to the Future II, "what if the multiple Martys running around 1955 met up and did it?" Plus, the obligatory line about "it's not gay if you're..." slightly alludes the actual film's homophobic question posed by Marty regarding the ramifications of going on a date with his mom, "what if I go back to the future and I end up being...gay."
I agree it's a little more gross than funny, and I don't quite understand the ending. But I'll always find hypothetical and alternate timelines intriguing. And if you believe in the theory of infinite universes created by the infinite decisions available, you must recognize that somewhere in the multiverse of the Back to the Future trilogy there is a dimension in which Marty really did give into his mom, and himself, and himself again. Just as there's the parallel timeline in which Biff gave himself that sports almanac.
What other "what if?" situations could be posed for the franchise? A couple months ago, Peter wondered, "what if Marty McFly's mother was gay?" What else you got?