The politics pursued by the administrations of heads of government in Mexico City since the second half of the 20th century have usually been more liberal than those of the rest of the country, whether with the support of the federal government—as was the case with the approval of several comprehensive environmental laws in the 1980s—or through laws recently approved by the Legislative Assembly. In April of the same year, the Legislative Assembly expanded provisions on abortions, becoming the first federal entity to expand abortion in Mexico beyond cases of rape and economic reasons, to permit it regardless of the reason should the mother request it before the twelfth week of pregnancy. In December 2009, the Federal District became the first city in Latin America, and one of very few in the world, to legalize same-sex marriage.

When was gay marriage legalized in Mexico City?