A federal judge in Kentucky ruled Wednesday that the commonwealth must recognize same-sex marriages performed in states where the unions are legal.

It is the latest in a string of judicial victories for proponents of same-sex marriage following the U.S. Supreme Court’s ruling in June in United States v. Windsor. The justices struck down part of the Defense of Marriage Act and said the federal government must recognize legal marriages between those of the same sex.

In Wednesday’s ruling, U.S. District Judge John G. Heyburn II said Windsor was only the latest in a series of Supreme Court rulings that has incrementally advanced the gay rights movement.

“Each of these small steps has led to this place and this time, where the right of same-sex spouses to the state-conferred benefits of marriage is virtually compelled,” Heyburn wrote.

The case before Heyburn did not require him to rule on whether Kentucky must issue marriage licenses to gay couples. But he said “there is no doubt that Windsor and this court’s analysis suggest a possible result to that question.”

Daniel J. Canon, a Louisville lawyer who represented the plaintiffs, said the statute that Heyburn found violating the U.S. Constitution’s guarantee of equal protection bans same-sex marriage as well as the recognition of such unions. That could open the door to marriages in the state, he said.

Heyburn was asked by four same-sex couples — married in either Canada or U.S. states that allow such unions — to make Kentucky recognize their marriages.

“It is clear that Kentucky’s laws treat gay and lesbian persons differently in a way that demeans them,” Heyburn wrote.

Striking them down, he said, will “make real the promise of equal protection under the law. It will profoundly affect validly married same-sex couples’ experience of living in the commonwealth and elevate their marriage to an equal status in the eyes of state law.”

In a statement, Kentucky Attorney General Jack Conway (D) did not offer a rousing defense of the law — “I did my duty and defended Kentucky’s constitutional amendment in federal court” — and noted that Heyburn said he would hold an additional hearing before issuing a final order.

“It would be inappropriate to comment further about the future of this case” until then, the statement said.

Heyburn noted that every federal judge who has considered challenges to state bans on same-sex marriage recognition has come to the same conclusion.

Federal judges in Utah and Oklahoma have struck down the bans in those states, although both decisions are being appealed. So is a decision by a federal judge in Ohio that the state must recognize for the purposes of a death certificate a union performed elsewhere.

There are dozens of lawsuits challenging similar bans around the country; Nevada recently announced that it would not defend that state’s ban in a federal court challenge.

And a federal judge in Virginia has said she will rule soon on a challenge to that state’s constitutional amendment. The state’s new attorney general, Mark R. Herring (D), recently announced he was changing the state’s legal position and joining couples who are seeking to have the ban struck down.

Same-sex marriage is now legal in 17 states, including Maryland, as well as the District.

Heyburn, appointed to the bench by President George H.W. Bush in 1992 on the recommendation of Sen. Mitch McConnell (R-Ky.), is the first federal judge nominated by a Republican president to rule for same-sex marriage proponents following the Supreme Court’s decision in Windsor.

He noted that his decision might not be popular in the state, where the constitutional amendment banning gay marriage was approved in 2004 by 74 percent of voters.

“Many Kentuckians believe in ‘traditional marriage,’ ” Heyburn wrote. “They may be confused — even angry — when a decision such as this one seems to call into question that view.”

But, he added: “Once the government defines marriage and attaches benefits to that definition, it must do so constitutionally.”

Heyburn said the tradition at issue in marriage “began at a time when most people did not fully appreciate, much less articulate, the individual rights in question.” He predicted that, “sometime in the not too distant future,” opposition to same-sex marriage might be seen the same as past hostility to integration and women’s rights.

Heyburn also rejected an argument advanced by the Family Trust Foundation of Kentucky, but not by the state, that Kentucky had an interest in making marriage between only a man and a woman because of the unique procreative aspect of heterosexual unions.

“The exclusion of same-sex couples on procreation grounds makes just as little sense as excluding post-menopausal couples or infertile couples on procreation grounds,” he wrote.

While plaintiffs in the case were happy, opponents of same-sex marriage expressed continuing disappointment with the federal judiciary.

“Today, yet another federal judge has entered the competition for lawlessness on the marriage front,” said Brian Brown, president of the National Organization for Marriage.

And the decision even sparked finger-pointing in McConnell’s rough-and-

tumble primary contest for reelection.

Challenger Matt Bevin tried to link McConnell to the decision, because of his past with Heyburn.

“It is no surprise that Judge Heyburn was Mitch McConnell’s general counsel and McConnell recommended him for the federal bench,” Bevin said in a statement. “Kentucky deserves better.”

McConnell criticized the ruling but did not mention his past with Heyburn.

“Regardless of one’s personal view on the issue, we should be able to agree that only the people of Kentucky, through the legislative process, should have the authority to change the law, not the courts,” McConnell said.

“I will continue to support traditional marriage and fight to make sure that Kentuckians define marriage as we see fit and never have a definition forced on us by interests outside of our state.”