I think that each country has its own rules for recognizing (or not) gay marriages conducted abroad (for example, Canada does, France does, I think Spain does.) In the U.S., I believe (someone correct me if I'm wrong) that they are recognized in New York, Rhode Island, Maryland, and Washington, D.C. However, no gay marriages, whether performed in a U.S. state or abroad, are recognized by the federal gov't, which means no federal benefits and no citizenship-by-marriage rights for the gay foreign spouses of Americans.