"If someone is gay and he searches for the Lord and has good will, who am I to judge?" Francis asked.
His predecessor, Pope Benedict XVI, signed a document in 2005 that said men with deep-rooted homosexual tendencies should not be priests. Francis was much more conciliatory, saying gay clergymen should be forgiven and their sins forgotten.
Francis' remarks came Monday during a plane journey back to the Vatican from his first foreign trip in Brazil.
He was funny and candid during a news conference that lasted almost an hour and a half. He didn't dodge a single question, even thanking the journalist who raised allegations reported by an Italian newsmagazine that one of his trusted monsignors was involved in a scandalous gay tryst.
Francis said he investigated and found nothing to back up the allegations.
Francis was asked about Italian media reports suggesting that a group within the church tried to blackmail fellow church officials with evidence of their homosexual activities. Italian media reported this year that the allegations contributed to Benedict's decision to resign
While stressing Catholic social teaching that calls for homosexuals to be treated with dignity and not marginalized, Francis said it was something else entirely to conspire to use private information for blackmail or to exert pressure.
Francis was responding to reports that a trusted aide was involved in an alleged gay tryst a decade ago. He said he investigated the allegations according to canon law and found nothing to back them up. But he took journalists to task for reporting on the matter, saying the allegations concerned matters of sin, not crimes like sexually abusing children.
And when someone sins and confesses, he said, God not only forgives but forgets.
"We don't have the right to not forget," he said.