Word that a soon-to-be-released Vatican document will signal homosexuals are unwelcome in Roman Catholic seminaries even if they are celibate has devastated gay clergy (search) — and raised doubts among conservatives about whether an outright ban can be enforced.

A Vatican official, who spoke on condition of anonymity because the document has not been released, said Thursday that the upcoming "instruction" from the Vatican's Congregation for Catholic Education (search) will reaffirm the church's belief that homosexuals should not be ordained.

In recent decades, Vatican officials have stated several times that gays should not become priests because their sexual orientation is "intrinsically disordered" and makes them unsuitable for ministry.

The latest document is scheduled to be distributed within weeks, just as an evaluation of all 229 American seminaries gets under way under the direction of the same Vatican agency developing the seminary statement. The review, called an Apostolic Visitation, was ordered by Pope John Paul II (search) in response to the U.S. clergy sex abuse crisis which erupted in 2002. Among the questions the evaluators will ask is whether "there is evidence of homosexuality in the seminary," according to the agency's guide for the inspections.

The Rev. Thomas Krenik, who taught for 10 years in St. Paul Seminary in Minnesota and wrote the guidebook "Formation for Priestly Celibacy," (search) worries that a blanket ban on gay priest-candidates will re-create the very conditions the Vatican wants to eradicate.

"For some men who happened to be homosexually oriented, they would go further in the closet," Krenik said. "That would be my fear, that this could become an even worse problem."

A gay American priest, who spoke on condition of anonymity because he feared reprisals from church leaders, said he and other gay clergy and seminarians felt "absolute horror" when they heard about the anticipated ban.

"I've spoken to gay priests who feel demoralized. I've heard straight priests say that they're embarrassed by it. I've heard priests both straight and gay seriously considering leaving," he said. "They couldn't believe that after centuries of either explicit or implicit welcoming of celibate gay clergy that the church would turn its back on them."

James Hitchcock, a church historian at St. Louis University and conservative commentator on contemporary Catholicism, said he thinks the ban is necessary considering that a study the U.S. bishops commissioned from the John Jay College of Criminal Justice (search) found most of the alleged abuse victims since 1950 were adolescent boys. But he conceded the policy will be difficult to enforce, since candidates for the priesthood can hide their sexual orientation. He's also concerned that gays truly dedicated to remaining celibate will be unfairly excluded.

"In theory, one might say judge each case on its individual merits, but some doubt whether it would be done in a proper way," Hitchcock said. "There isn't going to be an easy solution. I think if you have a policy statement that homosexuals ought not to be studying for the priesthood at least it gives seminaries a way to act."

Estimates of the number of gay seminarians and priests vary from 25 percent to 50 percent out of about 42,500 priests in the United States. Whatever the percentage, many Catholics are worried that the priesthood is becoming a homosexual profession. As the abuse crisis intensified, church officials discussed their concerns more openly and more urgently, even though experts on sex offenders said that homosexuals were no more likely than heterosexuals to abuse children.

Critics ranging from gay rights groups to advocates for victims have accused the Vatican of scapegoating homosexuals to divert attention from the church's failures to protect children.

Other seminary leaders have said a ban was pointless, since many clergy candidates do not realize they are gay until after they are enrolled or even ordained. And Krenik questioned whether the problem of subcultures of sexually active gays was as acute as the Vatican believes. He said that sexual activity was more prevalent a decade or so ago, before seminary administrators started clamping down on sexual misconduct — a trend that's intensified since the abuse crisis.

But Archbishop Edwin O'Brien, who leads the Archdiocese for the Military Services in Washington and is coordinating the seminary evaluations, told The Associated Press last week the church wants to "stay on the safe side" by enrolling seminarians who can remain celibate.

"There are some priests, I don't think there are many, some ordained people with same-sex attractions and they've done very well" remaining celibate, he said. "But generally speaking, in my experience, the pressures are strong in an all-male atmosphere."

Several priests challenged that argument and noted that heterosexual priests face their own temptations: The overwhelming majority of lay ministers who work side by side with clergy are women, yet no one has suggested banning heterosexuals from the priesthood.