16 US Court of Appeal judges will today begin a hearing to determine whether the names of two gay men who adopted a Louisianan baby can appear on the birth certificate.

Oren Adar and Mickey Ray Smith adopted the boy in New York in 2006 where gay couples can list both their names on the birth certificate.

Louisiana officials objected to adding both names to the certificate as, under state law, single people and unmarried couples cannot adopt.

However, at the district level and at a previous hearing by three of the sixteen judges at the Court of Appeal, their decision was overturned. Authorities requested a decision by the full complement of judges.

Kenneth D. Upton Jr., a lawyer for the civil rights group Lambda Legal, represents the gay couple. He said that allowing only one adoptive father on the Louisianan certificate would leave a “gaping loophole” in the US system wherein states credit each others’ laws.

He said: “An exception that permits states arbitrarily to ignore legal parent-child relationships as families travel throughout the United States would create unprecedented chaos and harm.”

Adoptive parents have won similar cases in Virginia, Mississippi and Oklahoma.