Argentina has become the first country in Latin America to legalise same-sex marriages, following a landmark senate vote carried live on national television.
The gay marriage proposal had the firm support of President Cristina Fernandez, but was strongly opposed by the Roman Catholic Church and evangelical groups, which drew 60,000 people to a march on Congress on the eve of the pivotal vote.
Approved by Argentina's lower house in May, gay marriage automatically became law this morning after it was approved by a senate majority. The law was adopted 33-27 following a 15-hour debate.
Supporters and opponents of the law held rival vigils through the night outside the Congress building in Buenos Aires.
Same-sex civil unions have been legalised in Uruguay, Buenos Aires and some states in Mexico and Brazil. Mexico City has legalised gay marriage. Colombia's Constitutional Court granted same-sex couples inheritance rights and allowed them to add their partners to health insurance plans.
However, Argentina has become the first country in Latin America to legalise same-sex marriage, which generally carries more exclusive rights than civil unions, including adopting children and inheriting wealth. The new law broadly declares that "marriage provides for the same requisites and effects independent of whether the contracting parties are of the same or different sex."
Nine gay couples have already married in Argentina after petitioning judges, but other judges have challenged the marriages as invalid.
The president, currently on a state visit to China, spoke out from there against the Argentine Catholic Church's campaign, and the tone she said some religious groups have taken.
"It's very worrisome to hear words like 'God's war' or 'the devil's project,' things that recall the times of the Inquisition," she said.
Mrs Fernandez's husband, former president Nestor Kirchner, has been a strong gay marriage supporter. Some opposition leaders have accused the couple of promoting the initiative to gain votes in next year's presidential elections, when Mr Kirchner, who is currently a congressman, is expected to run again.
But Edgardo Mocca, a political science professor at the University of Buenos Aires, said the senate vote about much more than political campaigns - it's a transcendent moment for Argentine society as it weighs whether rules of marriage should be determined by the church or the state.
Opponents of gay marriage also offered a civil union measure that gays and lesbians said would represent a major step backward by barring same-sex couples from adopting or undergoing in-vitro fertilisation, and by enabling civil servants to refuse to unify couples according to their "conscience."
"With this any civil servant could declare that blacks and whites can't join in a civil union, or Catholics and Jews," Senator Daniel Filmus complained, calling on fellow members of parliament to show the world how far the society has come. "Argentina is providing a demonstration of its maturity. The society has grown up. We aren't the same as we were before."
AP