DETROIT, MI -- Gay couples can now legally marry in Michigan.

Banning same-sex marriage is unconstitutional, the U.S. Supreme Court ruled Friday, striking down the Michigan law passed by voters in 2004 that limited marriage to heterosexual couples.

"The Fourteenth Amendment requires a State to license a marriage between two people of the same sex and to recognize a marriage between two people of the same sex when their marriage was lawfully licensed and performed out-of-State," the court found in a 5-4 decision.

Joint adoptions and tax filings are now possible for gay couples in Michigan, and across the nation, along with improved status in matters of insurance, hospital visitation, estate planning and other spousal rights and benefits.

April DeBoer and Jayne Rowse, the Hazel Park couple who sued the state because of their inability to jointly adopt their children, planned to gather with supporters to celebrate the decision in Ann Arbor around noon.

"Today is a great day for Michigan and our entire country," said William Greene, executive director of Equality Michigan in a statement. "Marriage equality is now the law of the land. Not so long ago, freedom to marry seemed like a impossible dream. Now, thanks to April DeBoer and Jayne Rowse from right here in Hazel Park - and many others - we've entered a wonderful new reality. All of us, no matter who we love, are free to marry in every state and territory of the United States."

The couple sued the state in 2012 after narrowly avoiding a car crash that left them wondering what would happen with custody of their three (now four) individually adopted children if one parent were to die.

The lawsuit led to a three-and-half-year process that included a nine-day federal trial in Detroit, followed by closely watched oral arguments in an appeals court in Cincinnati, and Supreme Court review that also included cases out of Kentucky, Ohio and Tennessee.

Asked immediately after the ruling what's next for the couple, Rowse said "We have to plan a wedding and adopt some kids."

Couples are likely to begin lining up at county clerk's offices for marriage license immediately.

They'll join 323 married gay couples who managed to wed the day after a Detroit federal judge ruled Michigan's ban unconstitutional on March 21, 2014, sparking a rush for marriage licenses before the 6th U.S. Circuit Court of Appeals issued a stay.

An estimated 14,598 same-sex couples live in Michigan, and about 7,299 of them plan to marry within the next three years, according to the Williams Institute at the University of California, Los Angeles, which studies LGBT demographics.

"I'll be on hand and available if people want to get married right then," said Oakland County Clerk Lisa Brown. "I can officiate and we are making sure that we do have enough staff in case we have a crowd."

State lawyers defended the ban by arguing voters could decide the issue on their own, citing a 2014 Supreme Court decision on the state's affirmative action ban in which that voter-approved law was upheld.

But on the issue of marriage, the court majority sided with lawyers for DeBoer and Rowse, who argued the ban violated fundamental, constitutional equal protection rights, and put children of same-sex couples at risk.

More coverage of the ruling and its impact around the state is available here.