(CNN)Romanians will go to the polls this weekend to vote in a referendum on changing the constitution to redefine marriage as being only between a man and a woman, in a move that opponents warn could breach human rights law and worsen homophobic discrimination.
Romania votes on defining marriage as only between a man and a woman
The vote, over Saturday and Sunday, was prompted by a petition started by an umbrella civil society group called Coalition for the Family and signed by nearly 3 million Romanians.
The constitution currently states that "the family is founded on the freely consented marriage of the spouses, their full equality, as well as the right and duty of the parents to ensure the upbringing, education and instruction of their children," according to a Coalition for the Family translation.
Romanians will vote on whether to narrow that definition of marriage to a union between a man and a woman, rather than "spouses."
Coalition for the Family, which describes its members as "upholding Christian and traditional values," argues that the constitutional change is needed to "preserve marriage" and defend the family.
The vote needs a turnout rate of 30%, or more than 5 million people, to be valid, according to Reuters news agency.
Romania, which only decriminalized homosexuality in 2001, does not currently allow same-sex marriage. But the proposed amendment to the constitution is likely to make any future change much more difficult.
More than 40 members of the European Parliament wrote to Romanian Prime Minister Viorica Dăncilă this week to express their dismay that the referendum was being held at all.
"This redefinition of family has the potential to harm children in all families by promoting the message that single parent families, non-married partners with children, grandparents raising their grandchildren, rainbow families, and all other families that do not fall under the narrow definition proposed by the referendum do not deserve to be recognized and protected," the letter said.
"Allowing this referendum to take place adds validity to anti-LGBTI rhetoric and encourages hate speech and violence against LGBTI individuals. We cannot allow that this legal limbo will place LGBTI individuals, including LGBTI children and children in rainbow families, in a vulnerable position and in flagrant violation of the fundamental right to non-discrimination as enshrined in the EU Human Rights Law."
The lawmakers also questioned why the governing Social Democrat Party had taken the unusual step of holding the referendum over two days rather than one. "We are concerned that this could be construed as a deliberate attempt to influence the outcome of referendum, by ensuring the 30% threshold of participation is met," they wrote.
Rights group Amnesty International warned that the change could lead to a breach of human rights law and worsen discrimination against the gay community in Romania.
"If approved, these changes would mark a dark day for human rights and equality in Romania," said Barbora Černušáková, Amnesty International's researcher on Romania.
"This referendum panders to homophobia and if approved and implemented, would not only breach Romania's obligations under international human rights law and EU law but would also severely impact the lives of families not based on marriage. It is an attempt to deny them the right to family life."
In August, large anti-government protests were held in Romania against what demonstrators say is a corrupt government.