Vatican City ? Reiterating its stand against sexually active gays in the priesthood, the Vatican also says in a new document that men with “transitory” homosexuality must have overcome their sexual tendencies for at least three years before entering the clergy.

The long-awaited “Instruction,” due to be released next week, was posted Tuesday on the Internet by the Italian Catholic news agency Adista. A church official who has read the document confirmed its authenticity; he asked that his name not be used because the piece has not been published by the Vatican.

Conservative Roman Catholics who have decried the “gay subculture” in seminaries will likely applaud the policy because it clarifies and perhaps toughens what the Vatican expects of seminarians and their administrators.

Critics of the policy warned that, if enforced, it will likely result in seminarians lying about their orientation and will decrease the already dwindling number of priests in the United States even further. Estimates of the number of gays in U.S. seminaries and the priesthood range from 25 percent to 50 percent, according to a review of research by the Rev. Donald Cozzens, an author of “The Changing Face of the Priesthood.”

The document, from the Vatican’s Congregation for Catholic Education, says the church deeply respects homosexuals. But it also says it “cannot admit to the seminary and the sacred orders those who practice homosexuality, present deeply rooted homosexual tendencies or support so-called gay culture.”

“Those people find themselves, in fact, in a situation that presents a grave obstacle to a correct relationship with men and women. One cannot ignore the negative consequences that can stem from the ordination of people with deeply rooted homosexual tendencies,” it said.

“If instead it is a case of homosexual tendencies that are merely the expression of a transitory problem, for example as in the case of an unfinished adolescence, they must however have been clearly overcome for at least three years before ordination as a deacon.”

Vatican prohibitions on sexually active gays becoming priests are not new, and a 1961 document says homosexuals should be barred from the priesthood. But the issue came to the fore in 2002, at the height of the clergy sex abuse scandal in the United States.

Thomas Plante, a psychologist who for more than 15 years has conducted evaluations of prospective seminarians for U.S. dioceses and religious orders, said the document would have an “enormous” ripple effect on the future U.S. priesthood if it is followed.

“Sexual orientation in almost all the evaluations I’ve done over 15 years hasn’t really mattered,” he said. “Now what’s coming out of the Vatican is that it matters in a big way. That’s a real challenge because we think that there are many, many, many gay men who are fabulous priests.”

The document, called an “Instruction,” is only five pages long, including footnotes. It was signed by the prefect and secretary of the congregation on Nov. 4, and says it was approved by Pope Benedict XVI on Aug. 31.