For the couples challenging the bans, the fight is about fairness and the right to be treated like other couples. A look at some of the plaintiffs:
During their 25 years together, Madison, Wisconsin, residents Katy Heyning and Judi Trampf prepared health care powers of attorney that gave each of them the ability to make medical decisions for the other. But they didn't have the documents with them when they traveled to New Orleans in 2002.
Heyning was there attending a conference, and Trampf joined her when it ended. The day after she arrived, Heyning suffered a seizure in their hotel room.
Trampf called 911. When their ambulance arrived at the hospital, personnel asked Trampf what sort of relationship she had with Heyning.
When she told them she was Heyning's domestic partner, they demanded to see the powers-of-attorney documents and told her that unless she had them in-hand, she wouldn't be allowed to make any decisions for Heyning.
That left Heyning's brother in charge as her next-of-kin. Heyning eventually regained consciousness but had trouble responding to questions. Trampf tried to answer for her, but hospital staff ignored her.
The couple later scanned their documents into their smartphones so they'll always have them with them. But Trampf said it's not fair.
"There was no standing in this medical center's mind legally who I was unless I had paper," she said. "That's when we started to realize, 'My God, we have to have all this paper on us that others don't just in case something happens."
Garth Wangemann had a new health care power of attorney form drawn up before undergoing surgery for lung cancer in 2011. He and his partner, Roy Badger, had older forms, but Wangemann feared they might be out of date.
When Wangemann developed complications that required doctors to put him in a medically induced coma for more than a month, Badger decided to keep him on life support. Wangemann's father wanted him removed and spoke to an attorney about trying to override Badger's power of attorney. The issue became moot when Wangemann woke up.
Wangemann, 58, of Milwaukee, said he wasn't upset that his father wouldn't have chosen to keep him on life support, but he was hurt that his father still didn't recognize Badger as his spouse after 37 years.
"Just the fact that my dad had the right to do that, or thought he did, hurt a lot," Wangemann said.
The couple later told a friend about the conflict, and their story eventually got passed on to the ACLU, which reached out to them earlier this year about joining the lawsuit.
"It was a surprise to us that they were even interested," said Badger, 57.
Amy Sandler and Niki Quasney didn't plan to get married until they could tie the knot in Indiana.
Cancer changed that.
The two women, inseparable since they met in 2000, were happy together as they moved around the country, finding acceptance in such places as St. Louis, Las Vegas and Chicago.
But Quasney was diagnosed with ovarian cancer in 2009, so two years later, the couple moved to her hometown of Munster, Indiana. They have two daughters, ages 3 and 1, and wanted them to grow up near Quasney's family.
In Indiana, people weren't as accepting. They were told they couldn't obtain a family membership from a gym and when they took one of their daughters to a hospital for a blood test, staff members questioned who Quasney was.
"When we moved to Indiana, we were treated like we were strangers," said Sandler, 37. "For the first time in a town that we were living in, we were bumping up against hurdles that we never faced. It was really frustrating."
The couple had a civil union in Chicago in 2011 so that Quasney, a 38-year-old former teacher, could be placed on Sandler's health plan. They married last August in Massachusetts near a cottage they visit regularly.
Neither of those ceremonies counted in Indiana until April, when a federal judge ordered the state to recognize their marriage because of Quasney's advanced cancer. They wanted Sandler to be listed as Quasney's spouse on her death certificate and feared Sandler would have difficulty obtaining death benefits if their union wasn't recognized.
Sandler said the couple wants other people to have the same rights.
"It's something we hope changes with the next decision," she said. "Because everybody wants to have the freedoms that they deserve."
For Bonnie Everly and Lyn Judkins, of Chesterton, Indiana, a spring health crisis turned into one of their worst nightmares.
Everly, 56, was hospitalized for six days in March after the carbon dioxide levels in her blood soared and she nearly lapsed into a coma. During that hospital stay, she had a terrifying middle-of-the-night setback that made her fear she was dying.
But because she and Judkins, 58, aren't relatives, Everly couldn't get hospital staff to call Judkins, even though they have been together more than 13 years.
"They said, 'We can take care of you,' but I said 'I need her!'" she recalled.
A night custodian finally helped Everly contact Judkins, who arrived at the hospital at about 4 a.m., only to face a 15-minute wait before staff would admit her into Everly's intensive care unit room.
While they could get married in a state where same-sex marriage is legal, Everly said the legal protections that would bring would vanish once they returned to Indiana. So they joined a lawsuit filed in March by national gay rights group Lambda Legal, which is one of several challenging Indiana's gay marriage ban.
Associated Press writers Rick Callahan in Indianapolis, Todd Richmond in Madison, Wisconsin, and M.L. Johnson in Milwaukee contributed to this report.
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