A referendum in Romania aimed at changing the definition of marriage to exclude same-sex couples has failed after turnout fell well below the threshold.

Final results published on Monday showed a voter turnout of just over 20 percent which was well below the 30 percent needed to validate a referendum.

Barely one-fifth of Romania’s 19 million voters turned out to cast their ballots in the weekend referendum which had drawn heavy criticism from rights groups and the European Union.

The vote aimed to change Article 48 of the constitution, from defining marriage as the union between two “spouses” to the union between “a man and a woman”.

Of the 3.7 million who voted, just over 3.4 million – around 92 percent – were in favour of the proposed change, the electoral office said.

Pavel Chirila, founding member of the Coalition for Family, which initiated calls for the referendum, said it reiterated the Orthodox values of the Romanian majority.

“Romania is a Christian Orthodox country, we want the notion of marriage clearly defined in the constitution,” said Chirila.

Opponents of the initiative, however, warned about the negative impact of the change on the rights of same-sex couples and single parents.

“This way of redefining the family has the potential of affecting children from all families by promoting the idea that single-parent families, formed by non-married partners, children raised by grandparents, rainbow families and all other families that do not fall under the narrow definition proposed by the referendum, do not deserve recognition and protection,” stated a letter addressed to Prime Minister Viorica Dancila.

Romanian civil law clearly states marriage as the union between a man and a woman.