Step 1 : Introduction to the question "Which movie was the first released under a PG-13 rating?"
...In the early 1980s, producer Steven Spielberg released to movies rated PG. These movies - "Gremlins" and "Indiana Jones and the Temple of Doom" - contained far more violence than many were comfortable with. This prompted the MPAA to modify its rating system. It introduced the PG-13 rating in July 1984. The new rating allows children under 17 to attend the movie without a parent, but lets the parent know that some material may be inappropriate. The first official PG-13 movie released was "Red Dawn," the 1984 hit starring Patrick Swayze. Source: Cinematheia.com