Croatia will hold a referendum on 1st December to define marriage as being between a man and a woman, a parliamentary commission decided on Wednesday.

The commission voted 10-3 to hold a referendum on whether to constitutionally define marriage as being between a man and a woman.

The vote was taken after more than one-fifth of all voters signed a petition calling for a referendum on the issue.

Campaigners gathered more than 710,000 signatures in two weeks in a country of only 4.5m in support of a vote on changing the constitution to specify that marriage is the “life-long union of a man and a woman,” the Financial Times reports.

Croatia officially joined the European Union on 1st July.  

Romania has also debated amending its constitution to define marriage as between a man and a woman; Hungary did so last year. But nowhere has the issue caused such debate as in Croatia, a mainly Catholic country.

The campaign grew out of parents’ concerns over a new sex education curriculum introduced last year, but shifted its focus after France moved to legalise gay marriage. Croatian family groups say this was imposed on the French population despite significant opposition.

Zeljka Markic, founder of In the Name of the Family, a campaign group, denied the Catholic church was specifically backing it, or that it planned to move on to abortion.

A former journalist and doctor, Ms Markic said the campaign had received support from Catholics and some dioceses. But it was also backed by other religious communities, political parties and social groups, with thousands of people volunteering for free.

The campaigners are the first to have secured the right under Croatian law to hold a referendum, after gathering more than twice the required number of signatures.  

Opponents of the initiative have suggested that the issue is too sensitive to be put to a referendum.

However Croatia’s foreign minister Vesna Pusi?, who is also deputy prime minister and who is unhappy with the referendum proposal, said that this was not an option.  

She said that the signatures to put the move to the voters had been gathered, and there was very little the government could do to avoid a vote.

“I actually think it’s the kind of issue that shouldn’t be voted on in the referendum, especially minority rights because by definition … they could be easily endangered by a referendum [passed by] the majority,” she said. “However, unfortunately, this is at the moment how our constitution stands and we are debating this issue how to prevent this in the future.”