KANSAS CITY, Mo. >> A judge struck down part of Missouri’s gay marriage ban for the first time on Friday by ordering the state to recognize same-sex marriages legally performed in other states, saying state laws banning the unions single out gay couples “for no logical reason.”

The order means such couples will be eligible to sign up for a wide range of tax, health insurance, veterans and other benefits now afforded to opposite-sex married couples. Missouri Attorney General Chris Koster, who has defended the state’s ban on gay marriage, said his office was reviewing the ruling.

The decision comes in a lawsuit filed by 10 same-sex couples who legally married outside the state, including Arlene Zarembka and Zuleyma Tang-Martinez. The St. Louis couple, who married in Canada, said Friday’s ruling could boost their household income, and they plan to apply Monday for Zarembka to receive Social Security benefits as Tang-Martinez’s spouse.

“To me, it’s a real validation by the judge of our relationship and our commitment to each other,” Tang-Martinez said.

The American Civil Liberties Union, which is helping the couples, noted the ruling was a first in the state.

“We’re gratified that the court recognized that married same-sex couples and their families are no different than other couples, and that the Constitution requires them to be treated equally,” ACLU attorney Tony Rothert said. “This is not the first court to reach this conclusion, but it is the first court to do so in Missouri, so it’s a tremendous day for our state.”

Jackson County Circuit Judge J. Dale Youngs sided with the couples, who argue that their rights to equal protection and due process are being violated by Missouri’s ban on gay marriage. Youngs said the couples deserve the same recognition as opposite-sex couples who married in other states.

“The undisputed facts before the Court show that, to the extent these laws prohibit plaintiffs’ legally contracted marriages from other states being recognized here, they are wholly irrational, do not rest upon any reasonable basis, and are purely arbitrary,” Youngs wrote. “All they do is treat one segment of the population — gay men and lesbians — differently than their same-sex counterparts, for no logical reason.”

The lawsuit before Youngs only challenges Missouri’s refusal to recognize marriages legally performed outside the state, not laws that bar same-sex couples from getting married in Missouri.

Rothert said the ruling means that thousands of Missouri couples can now qualify for spousal government benefits and, on a smaller level, change their last names to match their spouse’s on their Missouri driver’s license.

The case is among at least three challenging Missouri’s ban: There is a federal challenge in Kansas City, and a St. Louis case focuses on city officials who issued marriage licenses to four same-sex couples to trigger a legal test of the ban.

The lawsuits are based on the same arguments that led the U.S. Supreme Court last year to overturn part of the federal Defense of Marriage Act that denied a tax, health and other benefits to legally married gay couples.

In Missouri, Youngs said he expects the state Supreme Court to “provide the last word on all of the important legal issues presented by this case.”

Same-sex marriage is now legal in 19 states and the District of Columbia. The ACLU has cases pending against 13 other states with such bans, including five cases currently before federal appeals courts.

Associated Press writers Summer Ballentine and David A. Lieb contributed to this report from Jefferson City, Missouri.