Two cities are expected to begin handing out marriage licenses to gay and lesbian couples this week.

A gay marriage law in the District of Columbia is expected to take effect Wednesday, but couples will have to wait the customary 3 days before tying the knot, making Saturday the earliest couples can marry.

Gay couples in Mexico City are also anticipating the start of a gay marriage law, most likely on Thursday, March 4. Mexico City's gay marriage law is a first for Latin America. It gives gay and lesbian couples all the rights and responsibilities of marriage, including the right to adopt children. Previously, the city government recognized gay couples with civil unions, but gay adoption was banned.

The governments of both cities have had to overcome similar obstacles to approve their law: interference from federal officials.

DC's gay marriage law faced rejection by Congress, which has final say on laws approved by the DC Council.

Republicans – led by Utah lawmakers both in the House and the Senate – attempted to do away with the law, but appear to have failed. Senator Bob Bennett and Representative Jason Chaffetz both introduced resolutions that sought to overturn the measure.

“The determination of marriage affects every person and should be debated openly, lawfully and democratically,” Bennett said.

Both measures remain bottled up in committees as the law reaches the finish line.

Mexico's federal government appealed to the country's Supreme Court in an effort to derail the start of the law. The federal Attorney General's Office argued that the law was unconstitutional because it “strays from the responsibility of the government to place a priority on safeguarding the interests of children.”

While the court has yet to review the federal challenge, it upheld the law last week in rejecting challenges brought by the governors of three states controlled by the conservative PAN Party. The governors had argued that the law would force their state governments to recognize the marriages of gay couples from Mexico City. The court, however, said the states did not have the legal authority to challenge the laws of another state or the nation's federal district of Mexico City.

Mass weddings are being planned for both cities.

Up to 400 couples are expected to exchange vows on Saturday, March 20 in the District in an attempt to break the current Guinness World Record. The event, titled “Our Time Has Come,” is being hosted by GLBT Wedding Services.

Mexico City officials say plans for two mass weddings to take place on March 13 and 20 are in the works.

BREAKING UPDATE: Opponents of DC's gay marriage law have appealed to the Supreme Court to halt its start.