It's because the 12 rating is becoming a 12A, which means you can get into the cinema if you're under 12, but only if there's an adult with you to say you can handle the film.
The first film to be given a 12A certificate is the spy movie The Bourne Identity starring Matt Damon.
Earlier this year there was a row when Spider-Man was given a 12 certificate. Some local councils thought this too high and reduced it to a PG.
Similar certificates to 12A already exist in other countries like the US, Australia and Canada.
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Is the new 12A film rating a good idea?
