Produced and directed by Daniel Karslake. With Mary Lou Wallner, Richard Gephardt, and Desmond Tutu. Distributed by First Run Features. 1 hour, 37 mins.

No MPAA rating.

Playing at Ritz at the Bourse.

Daniel Karslake's documentary For the Bible Tells Me So won't win any prizes for technique, but innovation surely ranks very low on this filmmaker's to-do list. Karslake has said that the movie is mainly intended as a feature-length primer that can be deployed in arguments with homophobes.

Directorially, the movie is unremarkable, with one conspicuous and unfortunate exception: when Karslake apes the supercharged empathy of an episode of Dateline on NBC, right down to the verging-on-schmaltzy music. Otherwise, the interviews with scholars parsing the Old and New Testaments are paired with the expected archival photographs and illustrations of biblical scenes. For the Bible is, strictly speaking, an educational film, with the artlessness that phrase implies.

The movie's ensemble portrait of parents (many of them ministers) with adult gay or lesbian children strives to demonstrate that homosexuality is a genetic predisposition, not a lifestyle choice, and that those who quote Leviticus to justify their animosity are guilty not just of intolerance but also of selective piety, an inability to understand historical context and poor reading comprehension.

Mary Lou Wallner, one of the staunchest advocates of gay rights in the movie, became a political activist after her daughter, Anna, committed suicide - the result, Ms. Wallner believes, of the letter she wrote to Anna rejecting her after she came out.

Chrissy Gephardt, a daughter of the former House minority leader Richard A. Gephardt and his wife, Jane, talks about enduring a sexless marriage to a man before falling in love with a lesbian friend, admitting the truth about herself, coming out, and eventually joining her father on the campaign trail, with his support and encouragement. Another profile subject is Bishop V. Gene Robinson of New Hampshire, the first openly gay bishop of the Episcopal Church.

Filmgoers and critics who are mainly interested in aesthetics will have little tolerance for this secular sermon. But there is no denying that the film, however inelegant, fills a need. The inevitable DVD should be packaged in a plain cardboard sleeve, so that viewers can carry it in their pockets, and if confronted by a homophobe, hand it over and say "Watch this, then get back to me." - Matt Zoller Seitz