Washington CNN  — 

A same-sex American couple whose daughter was denied birthright citizenship filed suit against the State Department on Thursday, joining a growing list of LGBTQ families turning to litigation to combat the policy.

Although Roee and Adiel Kiviti are both US citizens, as is their almost three-year-old son Lev, their six-month-old daughter Kessem was not granted birthright citizenship due to a State Department policy that considers her “born out of wedlock.” The Kivitis said they received official notice of the rejection in early July.

Roee Kiviti told CNN in a phone interview Thursday that even though they had been told by the passport agency to expected a rejection, “getting the letter in the mail, in writing so we can see this discriminatory policy was really just a punch in the gut.”

“We knew that we had to act for our daughter, for our family, for other families so they don’t have to deal with this,” he said.

The lawsuit was filed in the US District Court of Maryland by Immigration Equality, Lambda Legal, and pro bono counsel Morgan Lewis. Asked for comment, a State Department official said they do not comment on pending litigation.

“We’re confident that the law is on our side,” Roee Kiviti said. “Our daughter is a natural-born American. She deserves all of the privileges and responsibilities that come of that.”

Both of the Kiviti children were born in Canada using an egg donor and a gestational surrogate. When the Kivitis applied for Kessem’s citizenship, her application was processed not under the policy for children born abroad of two US parents, but rather flagged for surrogacy. Under the State Department policy on “assisted reproductive technology,” “a child born abroad to a surrogate, whose genetic parents are a U.S. citizen father and anonymous egg donor, is considered for citizenship purposes to be a person born out of wedlock.” Because Kessem was only biologically linked to Adiel and he was just months short of the residency requirement, her application was denied.

The Kivitis are not the only LGBTQ family to have sought legal recourse to the policy. According to a release from Immigration Equality, theirs is the fourth suit filed against the State Department by the LGBTQ immigrant rights organization. A federal judge ruled in favor of another same-sex couple who faced a similar hurdle under the State Department’s surrogacy policy in February. The State Department appealed that ruling.

Roee and Adiel Kiviti said that they’ve received outreach from a number of people saying they were personally affected or know people who were affected by the policy.

“Even one family is too many,” Adiel Kiviti said.

Although the Kivitis are confident in their legal fight, they said that their plight has been “very unsettling.”

“We were there when (Kessem) was first born, when she took her first breath, when she first cried. We were the first people to hold her, we gave her her first feeding, her first bath. She first slept on our chests. We are her only parents, the only parents she’s ever known. We are her parents as much as your children are yours,” Roee Kiviti said. “And to have that questioned is unsettling.”

“We know what a family is. Make no mistake, there’s no confusion on our end. We encourage the State Department to recognize that,” he added.

This article has been updated.