A gay married couple in Maryland sued Thursday to challenge the State Department's refusal to recognize the United States citizenship of their infant daughter, who was born in Canada via a surrogate this year.

The federal lawsuit says a U.S. State Department policy discriminates against same-sex married couples and unlawfully treats their children as if they were born out of wedlock.

An attorney for the plaintiffs, Roee Kiviti, 41, and Adiel Kiviti, 40, said their suit is at least the fourth such case to challenge the policy.

In February, a federal judge in California ruled that a son of a gay married couple has been a U.S. citizen since his birth. The State Department is appealing that decision. Two other federal cases are pending in Washington, D.C., and Georgia.

The State Department declined comment, citing pending litigation. The suit names Secretary of State Mike Pompeo as the lone defendant.

Roee and Adiel are naturalized U.S. citizens who were born in Israel. Their daughter, Kessem, was born via gestational surrogacy in Canada in February using Adiel's sperm and a donated egg.

Roee said he and his husband felt their privacy was invaded when a consular officer asked them questions about how their daughter was conceived and born.

"We are the only parents she has ever known. To have that questioned by your own government is very unsettling, to say the least," he said during a telephone interview Thursday.

The State Department determined that Kessem isn't a U.S. citizen because Adiel, the only parent with a biological connection to her, hadn't lived in the U.S. long enough to meet a five-year residency requirement under a provision of the Immigration and Nationality Act, according to the couple's lawsuit. But the five-year requirement is not meant to be applied to the children of married U.S. citizens, the couple's lawyers maintain.

Adiel moved to the U.S. in May 2015 and became a U.S. citizen in January. Roee has lived in the U.S. since 1982 and became a U.S. citizen in 2001. They married in California in 2013 and live with their daughter and two-year-old son, Lev, in Chevy Chase, Md.

"State Department policy unlawfully denies that the Kiviti family is a family at all," the suit said.

The lawsuit asks the court to rule that Kessem has been a U.S. citizen since her birth and seeks an order for the State Department to immediately issue her a passport.

'These clouds above your head'

Adiel said the legal challenge consumes precious time that he and his husband could be spending with their children.

"You don't want to have these clouds above your head," he said.

The couple is represented by attorneys from two New York-based legal advocacy groups, Immigration Equality and Lambda Legal Defence and Education Fund Inc., as well as the law firm Morgan, Lewis & Bockius. Their case was assigned to U.S. District Judge Theodore Chuang in Greenbelt, Md.

In the California case, government lawyers argued that citizenship for foreign-born children is not a "constitutionally enshrined right" for either the U.S. citizen or the child seeking to acquire citizenship. Rather, they said, it is a right granted by Congress.

"Further, the Supreme Court has underscored the importance of a biological connection between the child seeking to acquire citizenship and the U.S. citizen seeking to confer citizenship," government lawyers wrote in a January court filing.

However, U.S. District Judge John Walter concluded that the Immigration and Nationality Act doesn't require a child born during their parents' marriage to demonstrate a biological relationship with both of their married parents.