Everyone initially thought Cheryl and her brother, Jason, had a thing for each other, but they don't. However, there is some incest going on between Jason and Polly (though, they didn't know they were related). Polly — who's pregnant with Jason's twins in the first season — finds out that her and Jason's great-grandfathers were brothers. But after one of them kills the other, the family splits in two and distances themselves from one another with one side taking the name "Cooper." That would make Polly and Betty the cousins of Jason and Cheryl. Awkward.