(CNN) A same-sex married couple in Georgia sued the US State Department on Wednesday for refusing to recognize their daughter as a citizen.

Derek Mize and Jonathan Gregg, who married in New York in 2015, had their daughter Simone Mize-Gregg via surrogacy in England in 2018, their lawyer said in a statement. Both fathers are listed on the birth certificate.

When they applied for Simone's US citizenship, the US consulate in London rejected their application, the release said. "The Immigration and Nationality Act (INA) states that children of married U.S. citizens born abroad are U.S. citizens from birth so long as one of their parents has lived in the U.S. at some point, but the State Department routinely denies that right to same-sex couples and their children," the statement says.

"The State Department's policy is not only cruel, it is unconstitutional. The government refuses to recognize Jonathan and Derek's marriage and all of Simone's rights as a U.S. citizen," Aaron C. Morris, one of the couple's attorneys and executive director of Immigration Equality , said.

A State Department spokesperson declined to comment on the lawsuit, saying it does not comment on pending litigation.

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