BUENOS AIRES, - Thursday Argentina has become the first country in Latin America to legalise gay marriage after the Senate voted in favour.
The country's Chamber of Deputies has already approved the legislation.
The vote in the Senate, which backed the bill by just six votes, came after 14 hours of at times heated debate.
The law, which also allows same-sex couples to adopt, had met with fierce opposition from the Catholic Church and other religious groups.
Thousands protested outside Congress as debates took place inside.
At Sunday Mass, people were urged to protest on the eve of the vote by senators on whether to legalise gay marriage in the country.
"I came to defend marriage between man and woman, because I think any attempt against this is an attempt against natural law," said Angeles Navarro, one of the protesters.
The main slogan for the protest against the legislation was "the children have a right to a mother and a father".
There were demonstrations for and against the bill outside Congress as senators debated Small groups of demonstrators gathered in support of the bill.