(CNSNews.com) - A conservative advocacy group is bristling over the PG rating given to a new family film with a "pro-God theme."

According to the movie poster, the theme of Facing the Giants is, "Never give up, never back down, never lose faith."

But the movie poster also says parental guidance is suggested "for some thematic elements."

The American Family Association is outraged. It accuses the Motion Picture Association of America -- the movie raters -- of putting Christianity on the same level as sex, violence, and profanity because it might offend non-believers.

"The MPAA is controlled by Hollywood moguls known for their bitter opposition to Christianity," the American Family Association said in an email to supporters.

According to its website, Facing the Giants tells the story of a Christian high school football coach who uses his faith to battle the giants of fear and failure. The plot includes answered prayers, a medical miracle, and messages from God.

In one scene, the coach tells a student to change his ways with God's help. The boy tells the coach that not everybody believes "in all that honoring God and following Jesus stuff."

The coach tells the boy that no one's forcing anything on him: "Following Jesus Christ is the decision that you're going to have to make for yourself. You may not want to accept it, because it will change your life. You will never be the same."

The American Family Association believes that's the exchange that earned the movie its PG rating.

The AFA is urging its supporters to send an email to the MPAA, asking it to "stop their anti-Christian bigotry."

The group says the MPAA refuses to warn parents about movies that promote the homosexual lifestyle in a positive manner; and it wonders why a movie that bills itself as "a powerful experience for the whole family, inspiring viewers to live with faith, hope, and love," would need a warning attached to it.

The movie is scheduled for release in September.