It was an unlikely romance. Félix had narrowly avoided jail after defrauding a hospital and throwing his sister’s baby in a rubbish skip. Niko had just fathered a child with a surrogate mother who ran off with his ex-boyfriend.

But when the two men kissed during the finale of Brazil’s hit soap opera Amor à Vida last week, the Latin American country came to a standstill. It was the first time Brazil’s powerful Globo television network had aired a kiss between two male characters in its 49-year history – a turning point for a country that is still deeply conservative in spite of a reputation for carnival and skimpy bikinis.

“Watching Félix and Niko kiss was like seeing Brazil win the World Cup,” says Jean Wyllys, Brazil’s first openly gay congressman. “It may seem like a joke but it’s not – this is a historic moment.”

In a country 15 times the size of France where a quarter of adults cannot read, television soap operas play a fundamental role in defining cultural norms. In 1975 a Globo soap paved the way for the legalisation of divorce in Brazil, the world’s most populous Catholic country. A study by the Inter-American Development Bank shows that birth rates since 1971 dropped in regions when they were linked up to Globo as women began to aspire to the network’s modern female role models.

In 2012 at least 40m Brazilians tuned in to the final episode of Globo’s Avenida Brasil soap, prompting electricity companies to take emergency steps to avoid blackouts and even forcing President Dilma Rousseff to delay a political rally.

But for Mr Wyllys, the scene between Félix and Niko in Amor à Vida was long overdue. A minor television network showed two male characters kissing as early as 1990. In 2005 Globo filmed a gay kiss but the scene was vetoed at the last minute. Typically, only the first 20-30 episodes of a soap, or telenovela, are written before it goes to air – the network then conducts nationwide opinion polls to decide how the plot should proceed.

While Mr Wyllys has been campaigning for a Globo gay kiss for years, this time he was joined by hundreds of thousands of Facebook and Twitter users across Brazil, who used the hashtag “beijafelix” (“kiss Felix”) to put pressure on the network’s editors. Armed with the second-biggest Facebook community in the world, Brazilians have turned to social media to challenge the country’s social and political status quo, launching mass protests last year and threatening further demonstrations ahead of presidential elections in October.

Globo itself became a target of last year’s protests, with activists attacking its Rio de Janeiro headquarters with petrol bombs. Although the media conglomerate is privately owned by Brazil’s billionaire Marinho brothers, it has long been criticised for its cosy relationship with the authorities and its monopoly-like control over news and entertainment.

“The protests from June last year aren’t over yet and that is part of the reason Globo responded so quickly to public opinion this time around,” says Dennis de Oliveira, a media professor at Brazil’s USP university.

Facing competition from cable television, Globo is under pressure to please the country’s upper-middle classes – the section of society that most supported the #beijafelix campaign, according to Mr Wyllys.

“Every scene in the telenovela is a consequence of history. It is a response to the demands of the script and it reflects a moment in society,” Globo said in a statement. “Homosexual relationships were always present in our soaps and series in a very constant, responsible and natural way.” it said.

For the country’s growing legion of ultraconservative evangelical leaders, though, the final episode of Amor à Vida was anything but natural. The pastor and state politician Sargento Isidório, who describes himself as an “ex-homosexual”, fought back on Facebook on Wednesday, publishing a copy of a lawsuit he had filed against Globo.

“The family is the essence of society and should be preserved,” he wrote to public prosecutors.

Congressman Jair Bolsonaro, the rightwing former army chief known for blocking Brazil’s anti-homophobia law, has also attacked Globo, accusing its authors of trying to “spread” homosexuality.

As the popularity of the Catholic Church sinks to an all-time low in Brazil, evangelists have formed one of the most powerful voting blocks in Congress, pursuing an anti-gay agenda that has made it harder for the authorities to combat a wave of homophobic attacks. Between 2007 and 2012 the number of homophobia-related murders in Brazil almost tripled to 336, according to a report by the gay rights group Grupo Gay da Bahia. In part, though, this is because Brazilians are more open about their sexuality than they were in 2007, it says.

However, Walcyr Carrasco, the author of Amor à Vida, says the positive reaction he received after the soap’s finale last week is a sign that Brazilian society may finally be ready to accept a new “normal”. “I thought Brazil was a conservative country,” he says. “Well, that was until the last episode.”