(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.

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.

Read More