A federal appeals court on Tuesday struck down gay marriage bans in Nevada and Idaho.

A 3-judge panel of the Ninth Circuit Court of Appeals in San Francisco said the bans violate the Equal Protection Clause of the Fourteenth Amendment of the US Constitution because “they deny lesbians and gays who wish to marry persons of the same sex a right they afford to individuals who wish to marry persons of the opposite sex.”

It is the first unanimous appellate court ruling on the issue and the fourth to overturn state bans.

The decision also affects 3 additional states under the court's jurisdiction: Alaska, Montana and Arizona.

The court said its ruling would take effect immediately.

The bans were defended by Monte Stewart of the Coalition for the Protection of Marriage, who argued that allowing gay couples access to marriage would weaken fathers' “commitment to abide by the child's bonding norm.”

Judge Marsha Berzon questioned Stewart's arguments.

You have children with gay parents “who would be potentially in a stable relationship and would potentially have the financial and other benefits of marriage. And essentially your thesis is to deny those children, leave aside the parents for the moment, those benefits in order to send some vague messages to other people,” she said.

Nevada is expected to implement the decision.

Earlier this year, Nevada Governor Brian Sandoval, a Republican, withdrew the state's defense in the case less than a month after the court ruled it discriminatory to reject a person from a jury pool based on sexual orientation (SmithKline).

According to Tara Borelli, a Lambda Legal attorney representing the Nevada plaintiffs, Stewart's Coalition for the Protection of Marriage does not have standing to request review from the Supreme Court.

Idaho Governor Butch Otter, a Republican, called the court's decision “disappointing.”

“I will carefully evaluate the opinion, along with yesterday's surprising decision by the U.S. Supreme Court, and talk with legislative leaders and the Attorney General before determining our path forward,” Otter said in a statement.

Evan Wolfson, president of Freedom to Marry, applauded the ruling in an emailed statement.

“Today's decision from the Ninth Circuit brings to 35 the number of freedom to marry states, and 64% of the American people now live in a state where gay people will soon share in the freedom to marry. We now have more states that have ended the exclusion of gay couples from marriage than had ended bans on interracial marriage when the Supreme Court brought the country to national resolution in Loving v. Virginia. We hope that the other federal appellate courts will move swiftly to end the disparity and unfair denial that too many loving and committed couples in the 15 remaining states endure,” he said.