Hollywood bean counters have started calling them "God films." The typical faith-based indie has a tiny budget and most of the actors are amateurs or second stringers from television. It doesn't take much money to promote one because churches are eager to hold pre-release screenings that fire up clergy and volunteers to spread the word -- on foot and online.

Southern Baptist entrepreneurs in Georgia made the pro-marriage drama "Fireproof" for $500,000 and it grossed $40 million at the box office, before the DVDs started reaching Bible bookstores. The new Possibility Pictures team spent only $3 million making its first film, "Letters To God," which opens this week.

Studio people can do the math.

"Lots of people are interested in that 'Fireproof' business model," said Patrick Doughtie, who wrote the original "Letters To God" screenplay and helped direct the movie. "They don't really know what they're looking for in terms of content, but they know that these movies are reaching an audience and making some money."

Doughtie, on the other hand, knew exactly what he wanted to see when "Letters To God" reached movie screens. He began studying screenwriting in order to tell a highly personal story based on the life of his son, Tyler, who died in 2005 at the age of 9 after a battle with an aggressive brain tumor.

After wrestling with anger and depression, Doughtie finally realized how much his son's faith had touched the lives of the people around him, old and young, and especially other members of Grace Baptist Church in Nashville.

This provided the hook for a fictional story about a boy named Tyler who has brain cancer and begins writing letters to God full of questions about his own life, as well as prayers for his family and friends as they struggle with their fears that he will die. The letters end up in the hands of a postal worker who is struggling with alcoholism and the break-up of his own family.

After he had finished the basic script, Doughtie found a notebook in which Tyler had written some letters to God. This made him even more determined to find producers who were willing to tell the story with the faith element intact.

"All kinds of people are touched by cancer and they're going to know what this movie is all about," he said, days before the movie's April 9 release in 900 theaters nationwide. "But I didn't want to write a story that was just about cancer. I wanted to write a story about hope and about what needs to happen after a battle with cancer."

For years, the makers of these faith-driven films have insisted that they can serve as evangelistic tools to reach nonbelievers -- even though they are full of hymns, prayers, church services, mini-sermons and other acts of God that tend to appeal to people who are already in church pews.

Sure enough, most of the crucial scenes in "Letters To God" pivot on confessions of faith, accompanied by lilting flutes or heavenly choirs.

Even the most painful moments are squeaky clean. The alcoholic mailman doesn't shout a single curse when he hits rock bottom or when his wise local bartender refuses to serve him another drink. Tyler's mother, Maddy, is already a widow and, by the end of the movie, knows that she will lose her youngest son. Still, she loses her cool only once -- when her own mother reminds her of a biblical parable about faith. She shouts: "I wish everyone would stop quoting the Bible to me. It's not curing my son."

Doughtie said that he hopes nonbelievers will see "Letters To God," but he knows they will not be the primary audience. More than anything else, he hopes the movie will inspire church leaders to learn how to minister to families affected by cancer.

"People wanted to help us, but they didn't know how," said Doughtie. "They loved us. They prayed for us. They brought us casseroles. They wanted to help. ... But what are you supposed to do after you pat someone on the back and say, 'Hey, I'm sorry you lost your kid'?

"What we have to do is remove the stigma from childhood cancer. People in our churches need to take their blinders off and get more involved with cancer families."