In his ruling Wednesday, U.S. District Court for Northern California Jeffrey White, also ordered that health benefits be provided to the wife of a lesbian federal court employee, the Los Angeles Times reported.
White's ruling was the first since the Obama administration announced last year it no longer would defend the law, saying it considered it discriminatory and denied equal rights to gays and lesbians.
White ordered the Office of Personnel Management to enroll the wife of Karen Golinski, an attorney for the 9th U.S. Circuit Court of Appeals, in the health benefits program available to other federal judiciary employees.
"The court finds that DOMA, as applied to Ms. Golinski, violates her right to equal protection of the law … without substantial justification or rational basis," White wrote.
White's ruling dealt a setback to the conservative-controlled Bipartisan Legal Advisory Group, the U.S. House panel set up to defend the statute after Attorney General Eric H. Holder Jr. said the administration would no longer do so. During the hearing in December, the panel argued the act was enacted to safeguard and foster heterosexual marriage.
White, named to the federal bench by President George W. Bush, said tradition didn't justify targeting a specific group, the times said.
"The obligation of the court is to define the liberty of all, not to mandate our own moral code," White wrote. "The 'ancient lineage' of a classification does not render it legitimate."
If White's ruling is appealed, it would go through the 9th Circuit, where Chief Judge Alex Kozinski said in administrative orders the federal government's refusal to provide benefits to Golinski's spouse violates her rights.