July 29, 2013 -- Pope Francis departed from his predecessors' remarks on gay people, telling reporters today that he was not in a position to judge people based on their sexuality.

"If someone is gay and he searches for the Lord and has good will, who am I to judge?" Francis asked reporters aboard a plane returning to Italy following his first trip abroad as pope to Brazil.

The remarks caused a stir with some gay Catholics wondering if the newly elected pope, a Jesuit who made a career ministering to the poor and marginalized, was signaling a shift in Church doctrine.

In 2005, Francis' predecessor Pope Benedict XVI signed a document calling for a purge of gay priests and during his papacy equated gay people with pedophiles.

"It is remarkable and a decided shift in tone from the past," said the Rev. James Martin, a Jesuit priest and editor-at-large of America magazine. "It's probably the most positive statement that a pope has ever made about gays and shows great mercy and compassion."

The comments constituted a shift in tone, Martin said, but that trickles down to changes in policy because "every bishop and archbishop will have listened to what he said... and his advice was not to judge [gay people] but to call them our brothers. It's a shift in tone from exclusion to inclusion."

The pope, speaking casually and appearing relaxed, candidly addressed a question about an alleged "gay lobby" inside the Vatican, including recent allegations in an Italian magazine that a trusted adviser of the pope had been involved in a same-sex relationship.

The pontiff was also asked about reports that some in the Vatican have used information about gay priests to blackmail them. The pope said gay people should be treated with respect, and that no one should use blackmail as an instrument to exert pressure.

Gay Catholics, who have long been marginalized by the church and sometimes denied communion, were cautiously optimistic about the pope's comments.

"This doesn't break new ground on the church's position on homosexual acts, but what we've seen from this pope is a real shift in emphasis," said Marianne Duddy-Burke, executive director of Dignity USA, a group that advocates for gay Catholics.

"For so long the rhetoric coming out of the Vatican -- about gay and lesbian people and same sex marriage -- has been horrifically damaging. For the first time we're seeing a pope who says: 'Who am I to judge,'" Duddy-Burke said.

Francis, since his election in March, has marked his papacy by reaching out to underprivileged and underserved communities. Unlike his two immediate predecessors, Francis was never in the Vatican hierarchy.

He most recently served as archbishop of Buenos Aires, Argentina, where he lived in a modest apartment and used public transportation. In 2010, then Cardinal Jorge Bergoglio said he would support same-sex civil unions but not gay marriage.