The issue achieved prominence in 2007 when a respected ambassador, Michael Guest, resigned after 26 years in the Foreign Service to protest the rules and regulations that he argued gave same-sex partners fewer benefits than family pets. Guest said he was forced to choose "between obligations to my partner, who is my family, and service to my country," which he called "a shame for this institution and our country."

Guest was a member of Obama's State Department transition team.

In the letter, which was organized by the group Gays and Lesbians in Foreign Affairs Agencies, the signatories wrote, "We believe that no colleague of ours is a second-class colleague, and no colleague's family is a second-class family." Many of the disparities could be resolved with an order from Clinton's office, the letter said, though some would require legislation.