An adult may bring a minor to any mpaa rated film except NC-17 and XXX.

PG-13 is an unrestricted rating.It is reccomendational.Under 13s can watch them at any age by themselves.They don't need to be accompanied.But MPAA suggests under 13s shouldn't watch PG-13 rated films without their parents or guardians.

Children can watch it with 13 or older. For a 8 year old, not only parental guidance is suggested, but some material may be inappropriate. Adult guardians will not be required, but the parent have been warned. "G- General Audiences (1968-present) All ages admitted PG- Parental Guidance Suggested (1972-present) All ages admitted PG-13- Parents Strongly Cautioned (1984-present) Some material may be inappropriate for children under 13 R- Restricted (1968-present) No children under 17 - requires accompanying by parent or other adult guardian NC-17- No Children 17 and Under Admitted (1990-present)" "In 1984, explicit violence in the PG-rated films Indiana Jones and the Temple of Doom and Gremlins were "the straws that broke the parents' backs". Their complaints led Hollywood figure Steven Spielberg, director of Temple of Doom and producer of Gremlins, to suggest a new rating to MPAA president Jack Valenti. Spielberg's suggestion was for an intermediate rating of PG-13 or PG-14. On conferring with cinema owners, Valenti and the MPAA on July 1, 1984, introduced the PG-13 rating, allowing in children over 13 years of age without a parent or an adult guardian, but warning parents about potentially shocking violence, cursing, and mature subject matter that may be inappropriate for children under 13; though weaker than an R rating, PG-13 is the strongest unrestricted rating." Source and further information: http://en.wikipedia.org/wiki/Motion_Picture_Association_of_America_film_rating_system