Pope Francis on Monday continued to recast the Catholic Church’s image by focusing on its inviting, merciful aspects, this time shocking a planeload of reporters by saying of homosexuality: “Who am I to judge?”

“If they accept the Lord and have goodwill, who am I to judge them?” the leader of the world’s 1.2 billion Catholics said in a remarkably candid and off-the-cuff news conference en route to Rome from Brazil. “They shouldn’t be marginalized.”

The pope’s seemingly casual remark was another example of his approachable style, which was on full display during his visit to Rio de Janeiro for World Youth Day. He carried his own bag onto the plane and traveled around Rio in a small Fiat without being shielded by hordes of security guards. He met with recovering drug addicts in a hospital and condemned inequality in a visit to crime-ridden slums.

He made his comments about gays, signaling that the church looks on them as brothers and sisters, as he fielded questions from reporters for an 80-minute stretch, at times leaning on the back of an airplane seat as if he were just another passenger. With his predecessor, Pope Benedict XVI, reporters had to submit questions ahead of time, and the Vatican decided which ones the pontiff would answer.

Church insiders say this is the first time in recent memory that a pope has given so much time to reporters — and done so off-script. Francis’s brief papacy has been marked by the candor of his comments on atheism, poverty and now, homosexuality, a topic that was broached when a reporter asked about allegations of corruption within a “gay lobby” of priests at the Vatican.

“When I meet a gay person, I have to distinguish between their being gay and being part of a lobby,” Francis said, according to a transcript provided by the National Catholic Reporter. He added that “the tendency [to homosexuality] is not the problem . . . they’re our brothers.”

The news conference marked the first time that Francis has addressed homosexuality during his four months as pontiff.

His predecessor made remarks that many gay Catholics interpreted as hostile. Even though Benedict called on Catholics to show “great respect for [gay] people,” he oversaw the publication of a church document that called homosexual inclinations “disordered” and called for men with “deep-seated” gay tendencies to be barred from the priesthood. He also said same-sex marriage was an insidious threat to the common good.

So Francis’s remarks were greeted warmly by advocates for gay and lesbian Catholics, who spoke of suddenly feeling welcome instead of being outcasts.

“Pope Francis today uttered some of the most encouraging words a pontiff has ever spoken about gay and lesbian people,” said a statement by Equally Blessed, a coalition of four groups working with LGBT Catholics and their families.

Marianne Duddy-Burke, executive director of Dignity USA, an activist organization for gay, lesbian, bisexual and transgender Catholics, said the pope’s words will make many feel accepted by their church for the first time.

“Just imagine if you’re somebody trying to come to terms with your identity and hearing the pope acknowledge that you can be a person of faith and goodwill, and still be gay or lesbian, and how that contrasts with somebody saying that your love for another person of the same sex is going to bring down society,” she said. “There’s such an empowerment and sense of acceptance.

“I don’t think anybody expected any kind of overnight change,” Duddy-Burke added. “What we find hopeful in this is that there may be the door opening a little bit, and I think the next step would need to be an indication that there’s a willingness to listen to the stories and the experiences of LGBT people and of our families, and hear of our challenges of staying in the church and also what gifts we have to offer.”

Others said bigger changes are sure to follow.

“I think change in the church is evolutionary and not revolutionary,” said Francis DeBernardo, who heads New Ways Ministry, which works with gay Catholics and their families. “If we want to see real change, we have to take it step by step. We’ve been waiting for this first step for a long time. No one in the papacy has taken this kind of step, ever.”

The remarks Francis made on the plane underscore his reputation as a conservative and a pragmatist. In 2010, as cardinal of Argentina, Francis worked behind the scenes to persuade bishops to support civil unions for gay couples — primarily because he saw them as a way to ward off full-fledged marriage for gays.

Many Catholic commentators said the pope’s remarks, while stylistically different, were similar in substance to previous church doctrine.

In a statement on his Web site, William Donohue of the Catholic League said Francis is carrying on a policy enunciated by Benedict:

“Pope Benedict XVI, responding to the homosexual scandal in the Catholic Church . . . did not make it impossible for gays to enter the priesthood; he simply made it more difficult for those who were practicing gays to enter. Pope Francis said nothing to contradict what his predecessor said.”

Chad C. Pecknold, an assistant professor of theology at Catholic University who has written on the papacy, said that “people are right to perceive a change in tone and that that tone is a pastoral tone on the question of homosexual inclinations.”

Pecknold noted that Francis told reporters he did not mention abortion or same-sex marriage before his trip to Brazil because he wanted to sound “positive.”

Rather than “beginning the conversation with what the church teaches about what one shouldn’t do,” Pecknold said, the pope “wants to begin the conversation about what it means to enter into the mercy of God.”

Michael Sean Winters, an author who writes for the National Catholic Reporter, said Francis’s take on gays in the church is part of his graceful style.

“He’s not saying, ‘Look, there is no sin,’ although he does tend to talk of the sins of savage capitalism more than he does of secularizing humanists. He is leading with mercy. He never wags his finger.”

Pecknold called Francis an “agent of renewal” for the church.

“I think the world likes a good comeback story,” he said. “There’s a sense in which the Catholic Church has been riled by scandal in the third quarter of the 20th century, and it’s time to come back from this.

“I think there’s a palpable sense that people want to see the church succeed. . . . I think there is this palpable sense that Pope Francis might be that agent of renewal who enables people to say, ‘It’s cool to be Catholic.’ ”