Correction: An earlier version of this story mischaracterized the proportion of Americans who don’t see Mormons as Christians. Polls show that one-third of Americans don’t see Mormons as Christians. This version has been corrected.

The first major independent poll of U.S. Mormons describes a conservative, devout community highly concerned about being accepted even as it embraces beliefs about gender roles, premarital sex and religious commitment that are well outside the mainstream.

The Pew Forum poll, to be released Thursday, offers an unusually detailed look at an American-born religion at a time when voters are craving information about GOP presidential front-runner Mitt Romney, a Mormon who was once a bishop in his church.

Experts on American Mormonism said the poll is the most detailed outside survey of the community, which makes up slightly less than 2 percent of the U.S. population.

It paints a picture of a group that is far more socially and politically conservative than the general population. Despite concerns about prejudice, Mormons also register unusually high rates of satisfaction with their own lives and communities. Some of the findings:

● Seventy-four percent of Mormons say they lean Republican, compared with 45 percent of Americans overall.

●Seventy-nine percent said sex between unmarried adults is wrong, compared with 35 percent of the general population.

● Fifty-eight percent of Mormons say the best kind of marriage is one with a husband as provider and a wife to care for the house and children; in the general population, 62 percent say it’s preferable for both partners to have jobs and take care of the home.

Some experts said the poll heralds a period in which Mormonism is being forced, by an interested public and by the explosion in recent years of independent Mormon bloggers, to open up, accept criticism from inside and outside the church, and shift from being a close-knit family to a creed that connects people by belief.

“This is a step toward a greater intellectual maturity in the church. Frankly, it’s about moving into the mainstream,” said David Campbell, a prominent political scientist from the University of Notre Dame, who focuses on religion and is a Mormon.

Some experts said the poll portrays Mormons as more uniform, observant and conservative than they are. The poll found that Mormons are more than twice as religiously committed as the general population and significantly more committed than such observant groups as black Protestants and white evangelicals.

“This sample looks like very busy, hyperactive Mormons,” said Marie Cornwall, a Mormon sociologist at Brigham Young University. “Who are these people? Many of us are really surprised at how religious this group is.”

Such comments reflect a rising debate in recent years about what Mormons really believe and do and the lack of data made public thus far.

Some sociologists blame church officials for not releasing more of the meticulous data they keep. Cornwall said that Mormon culture in recent decades has become more doctrinaire and that church members who don’t attend every required service or agree with every teaching might feel that they cannot fairly call themselves a “Mormon” to a pollster.

Campbell said a long history of prejudice has made Mormons defensive, wary of saying anything that might appear critical.

The poll reaffirms some familiar trends from previous research, such as that Mormons are likely to spend time primarily with their own. But the survey also fills in pieces of the puzzle.

Romney has overwhelming support among Mormons: 86 percent view him favorably. Even Mormon Democrats view him as favorably as do Republicans overall.

Just half of Mormons have favorable views of Jon Huntsman, also a Mormon, who is a former Utah governor and former Obama administration ambassador to China. Only 25 percent view President Obama favorably, half the rate of the U.S. general population.

More-educated Mormons are far more religiously committed than less-educated ones, a gap not often seen in other faith groups.

Terryl Givens, a religion professor at the University of Richmond who focuses on Mormonism, said the commitment of educated Mormons appears at odds with the fact that “cult” is the word most Americans most closely associate with the faith.

“It shows Mormons haven’t done a good job of conveying the appeal of their faith. They haven’t been able to move the discussion beyond gold plates and magic underwear,” he said.

The poll also presents this dichotomy: Mormons over­whelm­ingly say discrimination and misperceptions about them are their biggest problem, but they have high rates of optimism about future acceptance and are more satisfied with their lives and their communities than are Americans in general.

“That is Mormonism to a T,” said Cornwall, laughing. “Mormons tend to be very optimistic, but they also have a theology that says things are going to get worse. They plan for it, but in the meantime, they’re happy.”

The increase in Mormons living outside the West and the mini-boom in independent Mormon bloggers have changed a tightknit culture that appeared hemmed in by official voices. Church officials have responded to challenges by opening a bit of their vast and detailed records — including the publication, beginning in 2008, of the archives of the founding Mormon prophet, Joseph Smith.

Such changes reflect a shift for a community long in a defensive crouch. Mormons want to be accepted, but they also maintain beliefs and lifestyles that they affectionately call “peculiar,” Givens said. “Their very sense of identity is bound up with their sense of distinctiveness,” he said.

The poll reveals a bit of the complexity Mormons feel about their faith being mainstream.

Ninety-seven percent say their faith is part of Christianity, according to the poll, and the fact that many Americans — one-third, polls show — don’t see them as Christians is one of their primary concerns.

White evangelicals, with whom Mormons share many attributes, are the group least likely to see Mormons as Christians.

Yet many Mormons say they are very or somewhat different from Catholics and evangelicals, according to the poll.

“This is a people who are increasingly willing to learn about themselves,” Campbell said.

Church spokesman Michael Purdy praised the poll and said Mormons are “eager to participate in conversations that help the public get to know us better.”