Mexico's ratings board announced a long awaited revision of its ratings system - nearly a year after director Alfonso Cuaron and producing partner Jorge Vergara filed a lawsuit against the board for the C rating it gave their film, Y Tu Mama Tambien.

Incensed that the C rating - limiting the audience to age 18 and above - would prevent the target teenage audience from seeing it, Cuaron and Vergara complained that the ratings were arbitrarily decided by a small committee of government appointees. The lawsuit is still pending.

Although commercially limiting, the film's C rating did not stop it from breaking box office records on its opening week in Mexico.

The controversy did, however, fuel a debate on Mexico's antiquated ratings system which comprised AA for children's films, A for a General Audience, B for Teenagers and C for adults (18+).These have now been expanded to include a B15 for teenagers accompanied by adults and D for films with high sex, violence and foul language.

Y Tu Mama Tambien is expected to earn between $10m to $16m in the US where it opened via IFC Films - the theatrical distribution arm of the Independent Film Channel.