A new Vatican decree against gays in the priesthood has brought mixed reactions from U.S. Roman Catholic observers, with some seeing notable benefits and others predicting morale problems and a worsening clergy shortage.

The decree, approved by Pope Benedict XVI, is set for release next week. The Italian text was leaked Tuesday, and a Vatican official confirmed its accuracy to The Associated Press.

It says men should not be admitted to seminaries or ordained as priests if they practice homosexuality, have "deeply rooted homosexual tendencies" or "support so-called gay culture." Those with only "transitory" homosexual tendencies must be celibate three years before being ordained as deacons, the step before priesthood.

Some observers said it will be difficult to define what is meant by "deeply rooted" or "transitory" tendencies.

"I have no idea how they will apply it. It will just be a nightmare," said the Rev. Eugene Lauer of the New York-based National Pastoral Life Center.

A prominent gay priest, speaking anonymously, said the dozen homosexual clergy he has spoken with are "horrified" by the document.

The priest said that even emotionally mature gay men who are committed to practicing celibacy "will be completely discouraged" from applying, and gays already in the priesthood will be demoralized. Some clerics may even quit, he said.

"Our seminaries are likely to be depopulated to a significant extent," said the Rev. Donald Cozzens of John Carroll University. He cited estimates that put gay priests at 25 percent to 50 percent; Lauer guessed that 10 percent is closer to the mark.

Cozzens also warned that "the hunters might turn out to be the hunted," meaning that there are gay priests among Vatican officials, bishops and other church leaders.

But Brian Saint-Paul of Crisis magazine predicted little effect on the number of priests because, he said, seminaries and younger priests have become much more conservative the past two decades and moral liberalism is declining. "That generation is passing," he said.

The Rev. Richard John Neuhaus of First Things magazine said there is reason to believe that the decree will lead to a significant increase in candidates, because many would-be priests have been turned off by "the presence, and sometimes dominance, of a gay culture" in seminaries.

Neuhaus said the Vatican is basically reaffirming centuries of church teaching, with the new implication that "this time we mean it."

Jason Berry, a journalist who has covered priestly sexual abuse scandals since 1984, said the Vatican action was clearly prompted by the crisis and by the fact that most U.S. cases have involved priests and teenage boys.

"The priesthood is a huge closet. We all know that from the research that's been done," he said. He said that the Vatican is avoiding the central question of "Why can't the priesthood attract stable heterosexuals?" The answer, he said, is the ban on married men as priests.