Oscar Theory

When you live in New York and have a December birthday, and somehow you are still in the same grade you would be in if you had an early birthday. This has nothing to do with Oscar the Grouch.

Cooper: Hey Christian, do you know my friend Oscar from New York?
Christian: Yeah, when is his birthday again?
Cooper: December 4th, 2006. He is currently a senior in high school.
Christian: That proves the Oscar theory.
Cooper: The what?
Christian: Never mind.