SALT LAKE CITY — A federal judge has overturned part of Utah's law against polygamy in a case raised by the polygamous Brown family, made famous through their reality TV show "Sister Wives."

In a ruling released Friday, U.S. District Judge Clark Waddoups ruled language prohibiting polygamous cohabitation in Utah's 1973 statute to be unconstitutional.

However, bigamy — fraudulently acquiring multiple purportedly valid marriage licenses to enter into more than one legal marriage — remains against the law in Utah.

Kody Brown and his four wives, formerly of Lehi, filed the lawsuit in 2011, saying they weren't seeking legalization of plural marriage but that Utah's law violated their constitutional rights. Waddoups heard final arguments in the case in January.

"Sister Wives" sparked an investigation by the state, which ultimately forced the Browns to move from Lehi to Nevada in 2010.

In a statement released Friday, Brown said he and his family have waited years for what he called a "historical ruling."

"While we know that many people do not approve of plural families, it is our family and based on our beliefs," he said. "Just as we respect the personal and religious choices of other families, we hope that in time all of our neighbors and fellow citizens will come to respect our own choices as part of this wonderful country of different faiths and beliefs."

Fans of the show took to social media to congratulate the Browns.

"I cannot express my gratitude enough! What a wonderful day!" Robyn Sullivan Brown, one of Kody Brown's wives, posted Friday on Twitter.

"I feel blessed beyond belief tonight. No words can express how I love being free!" tweeted Christine Brown, another of Kody Brown's wives.

The family's lawyer, Jonathan Turley, called the ruling a victory for privacy as well as polygamy.

"What it means is these families can now walk out in public and be a plural family and not be afraid of being put under investigation or threatened with the loss of their children," Turley said.

The Utah Attorney General's Office had not yet reviewed the ruling and declined to comment Friday.

Email: mromero@deseretnews.com

Twitter: McKenzieRomero