U.S. Catholic educators are not changing how science is taught in Catholic schools, even though a prominent Austrian cardinal has said that evolution is incompatible with the teachings of the Roman Catholic Church.

But three leading U.S. scientists are so concerned that an essay by Christoph Schonborn, archbishop of Vienna, could signal a shift in the Catholic Church's long-standing support for evolution that they have asked Pope Benedict XVI to clarify the church's position.

"It has been very important that the Catholic Church has been supportive of evolution," said Lawrence M. Krauss, a physics professor at Case Western Reserve University in Cleveland who wrote the letter. Schonborn set off the rippling controversy last month with an opinion piece in the New York Times that stated evolution proponents had wrongly claimed that the writings of Pope John Paul II say evolution is compatible with church teachings.

Although the essay was not submitted on behalf of the Vatican, Schonborn told the Times that he had discussed it with Pope Benedict XVI shortly before then-Cardinal Joseph Ratzinger was elected pope in April. Schonborn, a member of the Vatican's Congregation for Catholic Education, has said there are no plans to issue new guidelines for teaching science in Catholic schools, although he believes that students should also learn about other theories.

Catholic educators are monitoring the debate but do not expect changes.

"Evolution should be taught as one of many theories," said Louis P. DeAngelo, who oversees curriculum for the Archdiocese of Philadelphia. "But the one true principle above all is there's one creator."

Karen M. Ristau, president of the National Catholic Educational Association, which represents Catholic schools, does not expect a shift in science instruction "unless this changes from theory to dogma."

Bishop Francis X. DiLorenzo of Richmond, chairman of the U.S. Conference of Catholic Bishops' Committee on Science and Human Values, said Schonborn was reiterating that the Catholic Church has always linked evolution to God.

The bishop said the essay did not contradict a December letter to U.S. bishops in which DiLorenzo advised: "Assured that scientific truth and religious truth cannot be in conflict, Catholic schools should continue teaching evolution as a scientific theory backed by convincing evidence."

DiLorenzo wrote the letter as the debate over teaching intelligent design in public schools was heating up. Intelligent design maintains that natural selection alone cannot explain the universe. Proponents say the intricacies of life suggest the presence of an intelligent, purposeful designer. The designer is not identified, but opponents say intelligent design is creationism in a new guise. On Monday, President Bush endorsed the teaching of the theory in classrooms.

The three scientists who have asked the Pope to clarify the church's position include two Catholics. "We hope very much that the Vatican would issue some form of clarification," said Kenneth R. Miller, a biology professor at Brown University who signed the letter.

Miller -- a Catholic and the author of "Finding Darwin's God: A Scientist's Search for Common Ground Between God and Evolution" -- said the church had long held that evolution could be seen as part of God's plan. The third scientist to sign the letter was Francisco J. Ayala, a biology professor at the University of California at Irvine. He is a former Dominican priest.

In the July 12 letter to the pontiff, first reported by the Times, Krauss wrote: "In his magnificent letter to the Pontifical Academy in 1996 regarding the subject of evolution, Pope John Paul II affirmed that scientific rationality and the church's spiritual commitment to divine purpose and meaning in the universe were not incompatible."

Krauss added: "It is vitally important . . . that in these difficult and contentious times the Catholic Church not build a new divide, long ago eradicated, between the scientific method and religious belief."

He has not received a reply.

Without clarity, adherents of intelligent design would use the cardinal's words to further their agenda, Krauss said. The Discovery Institute in Seattle, a leader in the intelligent-design movement, publicized Schonborn's piece on its Web site. An institute official had encouraged the cardinal to write the essay, a spokesman said. Schonborn told the Times that his essay was a response to a piece that Krauss had written for the newspaper in May and that had said: "Popes from Pius XII to John Paul II have reaffirmed that the process of evolution in no way violates the teachings of the church."

Schonborn told the Times that he had been "angry" for years that many writers and theologians had "misrepresented" the church's position. In his essay, he dismissed Pope John Paul II's widely quoted letter to the Pontifical Academy as a "rather vague and unimportant 1996 letter about evolution."

Schonborn wrote: "Evolution in the sense of common ancestry might be true, but evolution in the neo-Darwinian sense -- an unguided, unplanned process of random variation and natural selection -- is not."

Miller said Schonborn was wrong to say the neo-Darwinian theory of evolution must be atheistic. He said the church's support for evolution in a God-centered context had been affirmed over the years. Most recently, he said, that view was set forth by the Vatican's International Theological Commission in July 2004. Pope Benedict XVI headed the commission.

Cardinal Christoph Schonborn says evolution in the "neoDarwinian sense" is incompatible with Catholic Church teachings.