The ads are catchy. Upbeat music plays as the surfer, the artist or the skateboarder states his or her beliefs about life. They all end with, "And I'm a Mormon." On July 26, Pittsburgh became one of nine test markets for the advertising campaign that cheerfully counters stereotypes of Mormons as straight-laced, white, humorless and sexist. The campaign from the Church of Jesus Christ of Latter-day Saints includes a revamped website at www.mormon.org. The ads arrived on the heels of an anti-Mormon backlash by some gay rights activists on the West Coast. But the campaign's designers said it responds only...