A bit late to post, but better late than ever:
"The first Latin American country to legalize marriage between people of the same sex did so on the 15th of July 2010, after sixteen hours of debate. Argentina's Senate passed the measure, which grants gays "all the legal rights, responsibilities and protections that marriage brings to heterosexual couples" with a vote of 33 to 27, with three members abstaining. (The legislature's lower body already passed the law, and Argentina's president, Cristina Fernandez, has long been a strong supporter of the issue.) While Buenos Aires has become known as one of the more accepting cities in the region for gays, the bill was not without its opponents. Some 60,000 people marched on the capital in protest recently, led by evangelicals and the Roman Catholic Church"