Legal recognition for same-sex couples has been gaining ground here and there in Latin America, with some forms of recognition at the state or local level in Mexico, Argentina, and Brazil. (See Wikipedia's global summary for links to more info.) Now, there's progress at the national level in Columbia and Uruguay.
Last year, the Constitutional Court of Columbia issued two decisions granting partnership rights in relation to property, inheritance, health insurance and social security benefits. And this on April 17, that court issued another decision, extending equal rights with regard to pension benefits. Human Rights Watch praised the ruling, which followed a determination by a UN Commission that Columbia had violated its obligations under the International Convention on Civil and Political Rights.
Unfortunately, there doesn't seem to be a translation of the decision up anywhere, and I can't tell what the precise legal basis for these decisions is. My impression is that Columbia has incorporated its international human rights treaty commitments to at least some extent into domestic constitutional law. This is a marked contrast with the US, where our treaties are typically unenforceable in domestic courts and have no impact on domestic constitutional obligations.
While all of Columbia's progress on partnership rights has been through the judiciary, Uruguay enacted a civil union law that took effect April 18. It's important to note that while it's being called a "civil union" law, it doesn't appear to be like "civil union" laws in the U.S., i.e. providing all the legal consequences of marriage. Still, it's a huge step, and it's remarkable that the nation's Senate passed the bill unanimously last year.