An effort to repeal Argentina's groundbreaking gay marriage law is underway.

According to the Catholic News Agency (CNA), the socially conservative group Federal Network of Families (Red Federal de Familias) has begun a petition drive calling on lawmakers to nullify the law.

More than 1,300 gay and lesbian couples had tied the knot by January – six months after the law took effect – according to the gay rights group Federacion Argentina de Lesbianas, Gays, Bisexuales y Trans (FALGBT), which lobbied for passage of the law. The majority of those marriages were between men who had lived together for more than 12 years.

Juan Pablo Berarducci, national coordinator of the Federal Network of Families, told the Catholic news agency that the group hopes to collect 500,000 signatures by July, in time to force candidates vying for the government's top leadership positions to take a stand on the issue.

Argentina became the first Latin American country to legalize gay marriage after President Cristina Fernandez de Kirchner signed the law on July 21. Lawmakers approved the law over the strong objections of the Roman Catholic church; one cardinal called the movement to legalize such unions the devil's handiwork.

Gay and lesbian couples can legally marry in 10 countries on 3 continents.