Disney turned down the opportunity to make Back to the Future

Disney actually had first rights to the famous film "Back to the Future" but turned it down because they thought a certain element of the plot was too risque. In the film, the protagonist, Marty McFly, goes back in time to change the future. While back in time, his mom (now his age) falls in love with him and tries to start a relationship. Marty rebuffs her and she ends up with his dad. Disney thought this mother/son relationship was pushing the line, although Oedipus would be proud.