SAO PAULO, Brazil — Pope Benedict XVI used an open-air Mass yesterday to stress sexual morals, directly confronting what many here say represents the widest gap between the church hierarchy and a country with a reputation for permissiveness.

Taking advantage of the largest crowd he is expected to attract during his five-day visit to Brazil, Benedict called for rejection of those elements of popular culture that trivialize the church's prohibitions on sex out of wedlock.

"The world needs clean lives, clear souls and pure minds that refuse to be considered mere objects of pleasure," Benedict said during the Mass, which was held at a military airfield here and attended by hundreds of thousands of people. "It is necessary to say no to the elements of the media that ridicule the sanctity of marriage and of virginity before marriage."

Brazil has a reputation for being more sexually liberal than most countries, and it also has seen its percentage of Catholics drop from about 89 percent of the population in 1980 to about 64 percent today, according to recent polls. But the country's reputation had little to do with putting Catholicism in retreat.

A rising wave of evangelical Pentecostalism is largely responsible, and the members of those churches are generally even more conservative on sexual issues than are Catholics. According to a survey published this week by Brazil's Datafolha, for example, Brazilian Catholics are more tolerant of divorce, gay marriage, abortion and condom use than are Protestants.

If Benedict found himself preaching to the converted, perhaps that's exactly the crowd he wanted his message to reach.

"I think the pope wants us to be better Catholics, and he's not so concerned about the total numbers," said Jose Carlos Jr., 22, a biologist who rode a bus for 14 hours from his home town of Petropolis. "He wants to strengthen Catholics, and the message of chastity, I think, is being heard. I know many young people who have decided to not begin their sex lives until they are married."

During a meeting with Brazilian bishops later in the day, the pope urged them to energetically work to win back Catholics in Brazil with a traditional message of faith. The Rev. Jose Luiz Montezano, who attended the public Mass, said sexual morality issues are the toughest hurdles for church officials to get past when preaching in Brazil.

"Chastity is always the toughest subject here, because our culture is so thoroughly eroticized," said Montezano, who leads a parish of about 20,000 people near Rio de Janeiro. "It's very hard to counter, and not everyone in the church accepts our message on this."

The pope also suggested that legislators in various countries have been rejecting the church's traditional values — an apparent reference to recent efforts in Mexico and elsewhere to legalize abortion.

"Crimes against life in the name of individual liberties are being justified," Benedict told the bishops.

Though the majority of Brazilians say they oppose abortion rights, the nation's health minister recently called for discussions about holding a referendum to legalize abortion. The government has clashed with the church on several other matters, including stem cell research and its AIDS program, which energetically promotes the use of condoms and distributes them free. The public stands by the government in the matter, with 94 percent of respondents in a recent survey saying they support the use of condoms.

During the Mass, Benedict canonized the first-ever Brazilian-born saint, a Franciscan friar the pope said could serve as a model of chastity and of charity to the poor and sick. Friar Galvao, who was born in the 18th century, passed out prayers written on tiny pieces of paper that he encouraged people to eat.

The practice continues today, and locals have attributed thousands of miracles to the paper "pills."

The Vatican officially recognized two of the miracles: the birth of a baby to Sandra Grossi de Almeida, a woman believed to be infertile, and the sudden disappearance of life-threatening hepatitis in a 4-year-old girl.

Daniela Cristina da Silva, now 21, was the girl cured of hepatitis. She attended the canonization and was treated like a celebrity by a Catholic community that has flocked to a local monastery in recent weeks to collect an average of 30,000 paper pills a day.

"In terms of the importance of this for the community, I will never be able to grasp it fully," da Silva, who wants to be a fashion designer, said during an interview this week. "Some people want to touch me, and when they do they are overwhelmed with emotion and start crying. Then I sometimes start crying too, just to see how emotional they get about it."

Benedict concludes his first trip to Latin America as pope in Aparecida, about 100 miles from Sao Paulo, where he is scheduled to visit a drug treatment center today and open a conference of Latin American bishops tomorrow.