Mexico City’s legislative assembly recently voted to change the definition of marriage, legalizing gay marriage.

Representatives voted in December 2009 to change the Civil Code, which previously defined marriage as a union between a man and a woman and now provides that marriage is simply between two people. What makes this vote even more significant is the fact that the majority of Mexico’s population is Roman Catholic and the Church is opposed to gay marriage. Nevertheless, lawmakers in Mexico City went forward with the passage of this and other progressive legislation, including another legalizing abortion during the first trimester of pregnancy.

However, the new law changing the definition of marriage is not immune to opposition. Although the left-wing Democratic Revolution Party (PRD) led the legislative assembly in revising the Civil Code by a vote of 39 to 20 with five abstentions, opposition party leaders from the National Action Party (PAN), President Calderon’s party, say they will contest the revision. There are also limitations to this Civil Code revision, as it only applies to marriage within the limits of Mexico City. No other region in the country has passed a similar provision.

This is a large, progressive step forward for human rights in the region, with Mexico City leading the way as the first city in Latin America to affirmatively provide same-sex marriage rights. This follows a November 2009 Buenos Aires court decision striking down a provision of the city’s Civil Code that only allowed for marriage between a man and a woman. Mexico City now joins countries such as Canada, Belgium, and South Africa, which effectively allows for same-sex marriage. A handful of U.S. states — Massachusetts, Iowa, Vermont, New Hampshire, and Connecticut — have also legalized gay marriage. However, while some cities and countries are passing progressive laws, other countries, such as Uganda, are backpedaling. For example, lawmakers in Uganda are seriously considering passing a bill that would allow execution as a punishment for being openly gay, and also ensure that family and friends who do not report gay friends to the authorities are jailed.

Mexico City’s bold action in this area should be commended and Mexico City should be seen as a role model not only to the rest of Mexico and other countries in Latin America, but also to countries all over the world. Hopefully Mexico City’s legislative actions will create some momentum for this cause throughout Latin America and the rest of the world.