RIO DE JANEIRO — Brazil’s far-right government has a message for adolescents as the nation grapples with a stubbornly high teenage pregnancy rate and rising H.I.V. infections: Save sex for marriage.

“Our young people, by and large, are having sex as a result of social pressure,” Damares Alves, the minister of human rights, family and women, said recently as she encouraged abstinence. “You can go to a party and have lots of fun without having sex.”

To formulate her policy, Ms. Alves has made clear she consulted closely with the team behind a campaign called “I Chose to Wait,” started by evangelical pastors with a large social media following. In doing so, she has incited a heated debate about reproductive rights and sex education in Latin America’s largest nation.

Critics say the government’s new emphasis on abstinence blurs the line between church and state and could lead young people to make poorly informed decisions about sex that may be detrimental to their health.