It looks like a scene out of Sunday school — students in a southern Orange County, Calif., classroom huddle over Bibles as teacher Ryan Cox guides them in analyzing the relationship between God and Satan.

"If God is supposedly omnipotent, if he exists and is all-powerful, why let the serpent in the Garden" of Eden?" Cox asks. "Why let him hurt Job? Why let him tempt Jesus?"

But this lesson, at Aliso Niguel High School, is one of the growing number of Bible classes being taught in U.S. public schools.

There is broad agreement across the social, political and religious spectrum, and most importantly the Supreme Court, that the Bible can be taught in public schools and that knowledge of the Bible is vital to students' understanding of literature and art, including "Moby Dick," Michelangelo and "The Matrix."

But battles are raging in statehouses, schools and courtrooms over how to teach but not to preach.

As the number of these classes increases, civil libertarians, religious minorities and others fear that Bible lessons cloaked in the guise of academia may provide cover for proselytizing in public schools.

"Theoretically, it can be taught in an appropriate manner, but it takes the wisdom of Solomon to do it," said Mark Chancey, a professor of religious studies at Southern Methodist University in Dallas. "You're balancing academic quality, constitutional concerns and community sensibilities."

Although exact numbers are unavailable, experts agree that the number of Bible classes in public schools is growing because of new state mandates, increased attention to religion in public life and the growing prominence of two national Bible curricula.

Texas is the epicenter of the Bible battles. Legislation the governor signed in June set standards for such courses and could require every school in the state to offer them. Meanwhile, a legal battle in Odessa could invalidate the most widely used Bible curriculum.

Elsewhere, public high schools in Georgia will start offering state-funded Bible electives this fall. And in Riverside County, Calif., Murrieta voted in April to offer such a course in the fall.

"A lot of people thought it was one heck of a good idea. Others thought we were Satan's spawn," said Paul Diffley, a Murrieta school board member.

Religion has a long, volatile history in the nation's public schools, even leading to killings and church burnings in Philadelphia in 1844 when Roman Catholics protested after their children were forced to read a Protestant translation of the Bible in school. Over the next century, religious education ebbed and flowed, with districts and states taking varying tacks in how they integrated the Bible into the school day.

In 1963, a landmark Supreme Court decision declared school-led Bible readings and prayer unconstitutional. Justice Tom C. Clark emphasized in the ruling that the court did not intend to discourage academic study of religion.

"It certainly may be said that the Bible is worthy of study for its literary and historic qualities. Nothing we have said here indicates that such study of the Bible or of religion, when presented objectively as part of a secular program of education, may not be effected consistently with the First Amendment," he wrote.

Despite that legal opinion, a 2004 Gallup poll found just 8 percent of public school teens said their schools offered an elective Bible course.

High school English teachers and university professors say this lack of exposure to Bible tales has led to an education gap. A 2005 report by the Bible Literacy Project, which created a well-regarded Bible study course, found that while virtually all the teachers it surveyed said biblical knowledge was important to students' education, most felt that few students had a command of the subject.

However, when these classes are taught, they can be fraught with problems. A 2006 study by Chancey, funded by the liberal Texas Freedom Network, which surveyed every Texas public high school's Bible classes, showed what can go wrong. Of the 25 districts offering the classes during the 2005-06 academic year, the study found, all but three had minimal academic value and were not taught objectively, teachers were largely unqualified, and some classes were taught by clergy.

"The vast majority of Texas Bible courses, despite their titles, do not teach about the Bible in the context of a history or literature class," according to the study. "Instead, the courses are explicitly devotional in nature and reflect an almost exclusively Christian perspective of the Bible. They assume that students are Christians, that Christian theological claims are true and that the Bible itself is divinely inspired — all of which are inappropriate in a public school classroom."

The Bible debate is most volatile in Odessa, where in late 2005 the Ector County Independent School District adopted a controversial course created by the National Council on Bible Curriculum in Public Schools and offered it at two high schools.

The National Council program, endorsed by conservative organizations such as Concerned Women for America and the American Family Association, is used in 395 school districts in 37 states, according to the group's Web site. "Your first step to get God back into your public school," the Web site says.

Attempts to reach officials with the Greensboro, N.C.-based group were unsuccessful.

After the Odessa school board's 4-2 vote, the district's director of curriculum sent an e-mail celebrating the decision: "Take that, you dang heathens!" according to a lawsuit filed against the district in May by the American Civil Liberties Union, People for the American Way and eight parents.

"The folks pushing this curriculum in this form are not actually folks who want it to be taught constitutionally," said Lisa Graybill, legal director of the ACLU Foundation of Texas.

Kelly Shackelford, chief counsel of the Liberty Legal Institute, which is defending the district, said the lawsuit was rife with inaccuracies and he questioned the plaintiff's motives.

"It's the most widely used (Bible) curriculum in the country, in hundreds and hundreds of school districts," he said. "If they knock this out (in Odessa), they knock it out in places all over the country."

A competing curriculum, the Bible Literacy Project, took five years and $2 million to produce and has been praised by the National Association of Evangelicals, the American Jewish Congress and the First Amendment Center.

In southern Orange County, Cox's course appears to be a model of an objective, nonsectarian course.

The text is "The Layman's Parallel Bible," which offers four translations side-by-side. Cox tells the class at the start that some people believe the Bible is the literal word of God, while others think it is a collection of stories, but that that is irrelevant to the class's purpose.