A deeply divided Argentine senate battled on Wednesday over a same-sex marriage bill that, if passed, would make Argentina the first South American country to allow homosexuals to marry.
The proposal, passed by Argentina's lower house in May, would also give homosexual couples the right to adopt children.
The proposal has triggered large-scale protests and pitted Argentina's president Cristina Fernandez against the influential Catholic Church a year ahead of a presidential election.
Senators were expected to vote on the bill in the early hours of Thursday. Fernandez, currently on a state visit to China, has said she supports the bill on human rights grounds and is expected to sign it into law if it clears the senate.
Tens of thousands of opponents, from children to elderly nuns, braved near-freezing temperatures for a second day to protest outside Congress, where debate began in early afternoon and was expected to run well past midnight.
Opinion polls show a majority of Argentines support homosexual marriages, but there is less backing for same-sex couples to adopt children.
In their marathon debate, a number of senators in the 72-member upper house referred to their Catholic beliefs in presenting their reasons for opposing or supporting the bill.
Cardinal Jorge Bergoglio, archbishop of Buenos Aires, raised concern about the adoption clause of the bill, saying it was important to ensure that children have as role models "both a father and a mother".
Miguel Pichetto, head of the ruling party bloc in the upper house, told journalists it was crucial that minorities be treated justly. "It is the Congress that needs to ensure human rights," he said.
Only a small number of countries permit same-sex marriage, including The Netherlands, Sweden, Portugal, and Canada. In the United States, homosexual couples can marry in five states and in the capital Washington, DC, but not elsewhere.
Same-sex couples in Mexico City won the same rights as heterosexuals to marry and adopt children in December, under a law passed by city legislators. Uruguay allows same-sex couples to adopt children but not to marry.
Argentina's cosmopolitan capital Buenos Aires is known as a "gay-friendly" tourist destination with bars and hotels catering to homosexual clients.
