What's up with Hollywood's strange obsession with incest?

Ever notice how often movies and TV shows have characters who are related hook up? It's weird and creepy, and it happens way too often for it to just be coincidence. Story: http://nypost.com/video/hollywoods-strange-obsession-with-incest/ Twitter: http://twitter.com/nypost Facebook: http://www.facebook.com/NYPost