Feb. 13 (Bloomberg) — Kentucky was ordered by a federal judge to recognize same-sex marriages made in other states as similar challenges were filed in Louisiana and Missouri, escalating litigation over gay rights in courts nationwide.

U.S. District Judge John G. Heyburn in Louisville, Kentucky, yesterday said denying recognition to out-of-state same-sex marriages violates the equal-protection guarantee of the U.S. Constitution. He also said the in-state ban of gay unions may be vulnerable for the same reason.

Heyburn, a 1992 appointee of former President George H.W. Bush, a Republican, based his ruling in part on the U.S. Supreme Court June decision in U.S. v. Windsor invalidating a law limiting federal recognition of marriage to those between one man and one woman. Every federal court that has considered gay marriage since has ruled in favor of the right, Heyburn said.