Less than three weeks before it joins the European Union, Croatia is facing calls for a referendum that could rule out same-sex marriages in the largely Catholic nation, where conservatism appears to be on the rise.
Last month almost one-fifth of Croatia's population signed a petition launched by a Catholic Church-backed group calling for a referendum on whether to introduce a constitutional clause defining marriage as a "union of a woman and a man".
At the end of its virulent two-week campaign, the "In the Name of the Family" group had collected 710,000 signatures in the country of 4.2 million people.
The group's spokeswoman Zeljka Markic told AFP it had launched the campaign after seeing events "that worried us" in France, where gay marriage was legalised in May amid a wave of sometimes violent protests.
"We want Croatian citizens to have a chance to say... whether they believe that the definition of marriage as a union of a woman and a man should be a part of the constitution," said Markic, a doctor by profession.
The group plans to hand the petition to Croatia's parliament on Friday, which should then decide whether to call a referendum.
In a twist of irony, just a day later, Zagreb will host its 12th Gay Pride parade under the slogan "This is the country for all of us".
The success of the petition as Croatia prepares to join the 27-member EU, where a number of countries have passed laws legalising gay marriage, has sparked concern that Croatia "is getting more conservative", said social psychologist Mirjana Krizmanic.
"Croatia is going conservative but not in the positive sense of traditional values such as honesty, hard work or perseverance, but rather towards negative (ones) that are discriminatory and intolerant," she said.
"What is worrying is that young people support that."
Gay activists and human rights groups have criticised the referendum initiative as "homophobic" and called on Prime Minister Zoran Milanovic's Social Democrat government to block the move.
"Its main message aims to spread homophobia and affects human rights guaranteed by the constitution," said a joint statement by 20 rights groups.
Mirna Simic, a 37-year-old gay musician and writer, warned that a referendum was "discriminatory".
"Jesus would never sign this petition as he would not allow anyone to be treated as a second-class citizen," said Simic, appearing on a popular talk show on Croatian state television.
-- Sensitive issue --
In the Name of the Family rebuffs accusations of homophobia, saying "aggressive" gay rights groups are seeking to influence society.
The group apportioned a share of the blame to the government, whose more liberal attitude towards sexuality, including the introduction of now suspended sexual education classes in schools, is disapproved of by conservative groups.
"The authorities are trying to impose on people how to live, what to think, how to raise children and what to believe in.... I'm glad that Croatian citizens are opposing this by using legal mechanisms," said Markic.
Currently there is no specific definition of marriage in Croatia's constitution.
If the parliament proceeds with a referendum, Croatian law does not require majority voter turnout for the results to be valid, meaning a small number of voters could pass the clause, blocking any future legislation giving gays the right to marry.
Gay marriage is a sensitive issue that has long divided Croatia, where almost 90 percent of the population are Roman Catholics and the Church has a powerful influence.
In 2011 Pope Benedict XVI was given a warm welcome when he visited Croatia.
According to a recent report by the European Union's Agency for Fundamental Rights (FRA), some 41 percent of gays in Croatia feel discriminated against and isolated, compared to an average figure of 32 percent across Europe.
Croatia held its first gay pride parade in the capital Zagreb in 2002, when more than a dozen participants were beaten up.
Since then, parades have been organised in Zagreb annually without major incident, but always amid heavy security.
Last month, some 400 demonstrators took part in the nation's first march demanding same-sex marriage, while on Saturday, two government ministers and a mayor joined 500 people at a Gay Pride parade in Croatia's second city Split, where anti-gay violence marred a similar demonstration two years ago.
Croatia has taken some steps to recognise gay rights. In 2003 it extended to gay couples who have lived together for at least three years the same rights as those given to unmarried heterosexual couples, including state recognition of shared assets.
Mladen, a 52-year-old artist from Zagreb, said it was important that his 24-year relationship with his partner "is legally defined".
"I do not care how the life we have built together will be called, but I do care that we do not have problems in everyday life," Mladen, who did not want to reveal his last name, told AFP.
"If one of us ended up on a life support machine, the other one would not have the right to decide on what to do," he said.