"Rebel Without a Cause" was inspired by the early life of Marlon Brando

The plot for "Rebel Without a Cause" was inspired by the early life of Marlon Brando and "...Marlon Brando was originally cast for the lead role." (http://members.shaw.ca/giant/Film(3).htm). The movie was never meant to be an actually biography of Marlon Brando, just that his story of a wayward youth was compelling and movie maker Nicholas Ray felt that Brando playing a part similar to himself would bring about the best performance.

However, years went by and Brando was no longer suited for the part. This is where James Dean came in. James Dean wanted to be just like Marlon Brando and tried to live his life in his footsteps. Dean moved to New York and became a student of the same school that Brando went to. Columnist Sidney Skolsky said, "The best way to describe Jimmy Dean quickly is to say he is Marlon Brando seven years ago." and a magazine said that he was "The Boy Who'd Like to Be Brando." James Dean even enrolled in the same school.
Many of the people involved in the movie "Rebel Without a Cause" either owned homes on Fire Island, such as Lee Strasberg, or were frequent visitors such as Elia Kazan. Most of the homosexuals working on the movie were either from big cities or small towns, the only suburb they knew well was Sayville. It was also the only suburb they were all familiar and knew in common. They would often see the bad behavior and violent behavior of the kids in downtown Sayville. This was linked to Marlon Brando, since he himself was a wild, out of control student in Sayville. They were fascinated by the fact that children of upper middle class parents could behave so badly. Their theory was parental neglect.