The Catholic Church wants candidates for the priesthood to undergo psychological tests to screen out men who are unable to control their sexual urges.
The authors said screening would help avoid "tragic situations" caused by what they termed psychological defects.
The guidance says the voluntary tests should also aim to vet for those with "deep-seated homosexual tendencies".
Among other traits that might make a candidate unsuitable for the priesthood, the advice lists "uncertain sexual identity," and "excessive rigidity of character."
Seminarians should be barred if testing makes it "evident the candidate has difficulty living in celibacy: That is, if celibacy for him is lived as a burden so heavy that it compromises his affective and relational equilibrium", it says.
The advice stipulates priests must have a "positive and stable sense of one's masculine identity".
The document, approved by Pope Benedict, stresses that the screening must have the candidate's consent.
The Catholic Church has been rocked by a series of sex scandals in recent years involving paedophile priests, triggering lawsuits that have cost hundreds of millions of dollars in settlements.
A sexual abuse scandal that was first uncovered in the United States in 2002 and then spread throughout the world, involved mostly abuse of teenage boys by priests.
And a seminary in Austria was shut down in August 2004 after revelations that students openly indulged in homosexual conduct.
The Survivors Network of Those Abused by Priests, a US-based group of victims of sexual abuse, said the revised guidelines did not go far enough.
"Catholic officials continue to fixate on the offenders and ignore the larger problem: The Church's virtually unchanged culture of secrecy and unchecked power in the hierarchy," it said.
In the new document the Vatican said the early detection of "sometimes pathological" psychological defects of men before they become priests would help avoid tragic experiences.
"The Church ... has a duty of discerning a vocation and the suitability of candidates for the priestly ministry," said the document from the Vatican's Congregation for Catholic Education.
The testing by a psychologist or psychotherapist should aim to detect "grave immaturity" and imbalances in the candidates' personality.
Cardinal Zenon Grocholewski, head of the Vatican department that prepared the document, said homosexuality was "a deviation, an irregularity and a wound" that he said did not allow priests to carry out their mission properly.
The document said men with strong homosexual tendencies should not be admitted to the priesthood but it also made references to the control of heterosexual urges.
But gay groups have accused the Church of using homosexuals as scapegoats for the abuse scandals.