SALT LAKE CITY (AP) - The polygamous family featured on cable television's "Sister Wives" plans to challenge the Utah bigamy law that makes their lifestyle illegal.
Attorney Jonathan Turley is expected to file the lawsuit in Salt Lake City's U.S. District Court on Wednesday.
Turley represents Kody Brown and his four wives _ Meri, Janelle, Christine and Robyn. Kody Brown is only legally married to Meri Brown.
Formerly, of Lehi, the Browns belong to the Apostolic United Bretheran church, which practices polygamy as part of its faith.
The Browns and their 16 kids moved to Nevada in January after Utah authorities launched a bigamy investigation. No charges were ever filed, but Tuesday, Utah County Attorney Jeff Buhman said the investigation is ongoing.
Bigamy is a third-degree felony in Utah. Under the law, a person can be guilty of bigamy simply through cohabitation, not just by having multiple legal marriage licenses.
Turley said the lawsuit doesn't aim to challenge Utah's right to refuse to recognize plural marriage.
"All we're saying is that the state cannot criminalize the private relations of consenting adults," Turley told The Associated Press. "This lawsuit is less of a polygamy challenge than it is a privacy challenge."
Turley said the Browns and other polygamous families in Utah and the U.S. should be able to enjoy the same privacy rights as other families.
"In our view, Utah's law violates those rights, from due process to equal protection, from free exercise of religion and free speech," he said.
Utah Attorney General spokesman Paul Murphy on Tuesday said the state is prepared to defend its bigamy law.
Utah has not prosecuted a polygamist for bigamy since 2003, when former Hildale police officer Rodney Holm was convicted of entering a religious marriage with a teenager when he was already married to her sister.
Holm, a member of the southern-Utah based Fundamentalist Church of Jesus Christ of Latter-day Saints, argued that a ban on polygamy violated his constitutional right to practice his religion.
The Utah Supreme Court upheld the conviction in 2006, although in a dissenting opinion, the state's chief justice said the state unfairly applied the law to polygamists and "oversteps the lines protecting the free exercise of religion and the privacy of intimate, personal relationships between consenting adults."
The U.S. Supreme Court also denied an appeal from Holm in 2007. The high court banned the practice of polygamy, even in the context of religion in 1879.
Polygamy in Utah and across the Intermountain West is a legacy of the early teachings of Joseph Smith, founder of The Church of Jesus Christ of Latter-day Saints. Mormons abandoned the practice of plural marriage in the 1890s as a condition of Utah's statehood.
An estimated 38,000 self-described Mormon fundamentalists continue the practice, believing it brings exaltation in heaven. Most keep their way of life a secret out of fear of prosecution, although over the past 10 years an advocacy group made up mostly polygamous women has worked to educate the public and state agencies in Utah and Arizona about the culture.
"This is a good time for the lawsuit, we've tried to set that stage for this for 10 years," said Anne Wilde, co-founder of the polygamy advocacy group Principle Voices. "We've really tried to help people understand that this not a criminal lifestyle among consenting adults."