Why Michelle Williams' 'Blue Valentine' Sex Scene Rated NC-17

For all the hype about Natalie Portman's steamy lesbian sex scene with Mila Kunis in 'Black Swan,' the scene was still tame enough to earn an R rating from the Motion Picture Association of America's ratings board, which means it can (and will) be shown in theaters all over the country. Like Portman, Michelle Williams is on the receiving end of an oral sex scene in 'Blue Valentine' (opening Dec. 31). Despite the similarity of the scenes, however, the Williams scene earned her film an NC-17 rating, which would keep it out of most mainstream theaters, out of the movie-section ads in many newspapers and off the shelves of most mainstream DVD retailers.

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