The gay marriage fight is shifting to another court.

While the Supreme Court ruled gay marriage was the law last month, legal battles are brewing over employers providing benefits to same-sex spouses.

A Massachusetts employee is suing Walmart because the retailer denied health coverage for her spouse for years. Other lawsuits could pop up for similar claims, experts said.

The lawsuit filed Tuesday says Walmart, the country's largest private employer, discriminated against Jackie Cote when it denied her health insurance for her spouse. The lawsuit charges the retailer violated Title VII of the Civil Rights Act, the federal Equal Pay Act and a state law.

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In January 2014, Walmart started providing health benefits to same-sex spouses, but Cote wants to recover benefits denied to her before that date.

She has worked at Walmart since 1999 and has been married since 2004. Her spouse came down with cancer, which resulted in thousands of dollars in medical bills that weren't covered by Walmart, the lawsuit says.

The lawsuit argues that if Cote's spouse were a man, Walmart would have provided the benefits much earlier than 2014.

The size of the class could be hundreds to potentially thousands of workers, said Peter Romer-Friedman, deputy director of litigation with the Washington Lawyers' Committee for Civil Rights and Urban Affairs. Friedman is one of Cote's attorneys.

The federal Equal Employment Opportunity Commission ruled earlier this year that Walmart had discriminated against Cote. That ruling authorizes Cote to sue the big-box retailer.

Walmart told the Washington Examiner that its benefits coverage prior to January 2014 was consistent with the law.

There don't appear to be any other similar lawsuits, but experts say that is likely to change.

"I do not think it is an anomaly," said Teresa Renaker, an employee benefits lawyer who is a partner with the firm Renaker Hasselman. "There are lots of situations like Walmart and the federal government and large and small employers who may be providing benefits now but didn't do so until fairly recently."

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Lawsuits also could target companies currently denying benefits.

The Supreme Court didn't address benefits in its gay marriage ruling last month. There is nothing in the ruling that requires a private employer to extend benefits to same-sex couples, Renaker said.

The court ruled in 2013 that the federal Defense of Marriage Act was unconstitutional, but that ruling affected benefits only for federal workers, not private workers.

Most companies are unlikely to go to court over benefits, experts said.

If an employer wants to avoid a suit like Walmart's then "it is better to provide the benefits," said Howard Bye-Torre, an employee benefits lawyer with the firm Stoel Rives.

There will be some companies that exclude same-sex spouses due to their ideology, Renaker said.

The Supreme Court ruling did take away a potential defense for companies. Before the ruling, an employer could say it was following state law when benefits were denied if the business was in a state that outlawed gay marriage, Renaker said.

"The ruling removes any kind of non-discriminatory justification that might have existed before," she said.