Same-sex couples will be considered “family relationships” in immigration proceedings, according to Department of Homeland Security Secretary Janet Napolitano, a move that could help stem the deportation of those in gay or lesbian binational relationships.

Close family ties to the United States are a factor considered by authorities in deportation cases, and gay and lesbian advocates have long argued for same-sex couples to have the same immigration rights as opposite-sex couples.

“In an effort to make clear the definition of the phrase ‘family relationships,’ I have directed ICE to disseminate written guidance to the field that the interpretation of the phrase ‘family relationships’ includes long-term, same-sex partners,” Napolitano said in a letter.

Eight-four members of Congress signed a joint letter to Napolitano on July 31 asking for her to put into writing an order to prevent the deportation and separation of immigrants from their American citizen same-sex partners.

One of those who penned the letter, U.S. Congressman Michael Honda of California, said Napolitano’s response, which he received Thursday night, heralded “promising news.”

“In the wake of this important victory, we must take a step forward and continue the fight for immigration reform. Current immigration laws are tearing families apart and separating American citizens from their loves ones,” he said in a statement. “No one should have to choose between their spouse and their country, and no family should be left out of the immigration system.”

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There are an estimated 36,000 binational gay couples in the U.S. Two such couples have brought lawsuits challenging the Defense of Marriage Act, a U.S. law passed in 1996 that bars federal recognition of same-sex marriages and thereby denies various benefits given to heterosexual couples, such as the right to immigrate.

Rachel B. Tiven, executive director of Immigration Equality, called the announcement a “huge step forward.”

“Until now, LGBT families and their lawyers had nothing to rely on but an oral promise that prosecutorial discretion would include all families. Today, DHS has responded to Congress and made that promise real. The Administration’s written guidance will help families facing separation and the field officers who are reviewing their cases,” she said in a statement.

Tiven was referring to the prosecutorial discretion laid out in June 2011, when ICE Director John Morton issued a memo requiring staff to consider the circumstances presented in individual deportation cases, such as whether the person has close family ties to the U.S.

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