According to Ravid's research, PG- and G-rated flicks tend to earn more money, all other variables--including release dates and budgets--being equal.

FORBES: Magazine Article

Unlike most of the other outdoor cinemas mentioned here, this one is family-friendly with G- and PG-13-rated movies.

BBC: The best outdoor cinemas in Los Angeles

In the study, the relative handful of smoking scenes in G- or PG-rated movies didn't appear to influence a child's likelihood of trying cigarettes.

CNN: Should smoking trigger an R rating?

The MPAA has never revealed its guidelines for what qualifies a movie for a G, PG, PG-13, R or even the dreaded NC-17 rating, but Hollywood producers have a second sense for the tipping points between categories.

WSJ: Roger Ebert on Movie Ratings

They know a G film is harmless and a PG almost certainly is, and a PG-13 may or may not be.

WSJ: Roger Ebert on Movie Ratings