SALT LAKE CITY -- Reality TV stars Kody Brown and his four wives say they just want one thing: to be left alone.
As authorities investigate them for bigamy, the TLC "Sister Wives" family is asking a federal judge to overturn part of Utah's bigamy law because it bans them from living together and criminalizes sexual relationships between unmarried consenting adults.
"What they are asking for is the right to structure their own lives, their own family, according to their faith and their beliefs," said Jonathan Turley, their attorney, adding that the lawsuit is about privacy -- not polygamy.
The case in federal court in Utah, however, could open up the possibility that a way of life for tens of thousands of self-described Mormon fundamentalists could be decriminalized.
While all states outlaw bigamy, some like Utah have laws that both prohibit having more than one marriage license at a time and also ban adults from living together and having a sexual relationship.
The latter provision could include same-sex couples, unmarried heterosexual couples and those, like the Browns, who do not have licenses but have created within their homes a marriage-like relationship.
Turley, a noted constitutional expert, argued that, under previous U.S. Supreme Court rulings, such as one that struck down Texas' sodomy law, private intimate relationships between consenting adults are constitutionally protected.
The lawsuit doesn't aim to challenge Utah's right to refuse to recognize plural marriage, nor are the Browns seeking multiple marriage licenses, Turley said.
The display of the Brown family's polygamous lifestyle on cable television drew the interest of Utah prosecutors. The Browns are members of the Apostolic United Bretheran and practice polygamy as part of their religious beliefs.
Polygamy is the religious or cultural practice of a person having more than one spouse, which is defined as bigamy under law. Experts say it is a widely practiced, cross-cultural family structure found on every continent and in every major religion.
The family -- Kody, Meri, Janelle, Christine and Robyn, plus 17 children -- fled Utah for the Las Vegas suburbs in January after authorities launched a bigamy investigation. No charges have been filed.
Utah state attorneys say a bigamy prosecution isn't likely and that the lawsuit should be dismissed. And while authorities continue their investigation, prosecutors say, the probe isn't limited to bigamy. They have not provided anymore details.
Last week, U.S. District Judge Clark Waddoups heard arguments over whether the Browns have standing to continue the case, a decision based in part on whether the family has been harmed by the Utah law.
Waddoups will decide later whether to dismiss it altogether or set a trial date.
Utah's statehood was granted in the 1890s under the condition that plural marriage -- which was then-openly practiced by members of The Church of Jesus Christ of Latter-day Saints -- would be banned in the state constitution.
In the U.S., bigamy has been illegal under federal law since the 1860s. In 1887 and 1890, the U.S. Supreme Court rejected a legal challenge of the ban that argued that First Amendment protections should guarantee the right to continue the practice.
Church officials declined to comment for this story.
Despite the ban in every state, Mormon fundamentalists still continue the practice, most of them in Utah, where bigamy is a third-degree felony punishable by up to five years in prison.
Like most polygamists, Kody Brown only has a valid marriage license with his first wife, Meri. He married Janelle, Christine and Robyn only in religious ceremonies and the couples consider themselves "spiritually married."
Fewer than a dozen Utah cases have challenged the law -- none successfully. It has most commonly been used to prosecute polygamists typically when the defendants were also charged with other crimes, like child abuse.
The Utah Supreme Court upheld the law in 2006 as part of an appeal of a polygamist police officer's 2003 conviction on bigamy and child sex charges. The case began as an investigation into the child sex allegations.
In a dissenting opinion, the chief justice agreed that Utah unfairly applied its bigamy law to polygamists and that it "oversteps the lines protecting the free exercise of religion and the privacy of intimate, personal relationships between consenting adults."
Some scholars say polygamy should be decriminalized not just on First Amendment or privacy grounds, but because it would help society better regulate families.
Victims of abuse, which some believe is inherent in plural communities, might feel more comfortable seeking assistance if they don't also fear prosecution, Lyndon State College anthropology professor Janet Bennion said.
"Laws that criminalize polygamy isolate and alienate ... it's not polygamy per se that leads to abuse, that can be present in monogamy," Bennion said. "We really should allow more freedoms for any kind of alternative marriage.
"If we threaten polygamy, other forms will be threatened, such as gay and lesbian marriage," she said.
Law professor and polygamy researcher Maura Strassberg disagreed.
A supporter of gay marriage, Strassberg said polygamy is a "religious ideology that plays out in a form of relationship" and fears that decriminalization will essentially sanction an environment where abuse can thrive.
"I think it's important to keep (the bigamy law) on the books," Strassberg said. "It makes it clear that that sort of non-egalitarian, religiously coerced family is not consistent with our understanding of human rights."