Sister Wives star Kody Brown is going to court to defend the unusual family arrangement that catapulted him and his wives -- all four of them -- to television fame.

Utah law enforcement officials launched an investigation into whether Brown was violating a state ban on polygamy. Brown is formally married to one of his wives but the other three are sister wives, an arrangement sanctioned by the Mormon offshoot Apostolic United Brethren Church.

Brown filed a lawsuit challenging Utah's polygamy law by claiming that it violates the Equal Protection clause of the 14th amendment of the U.S. Constitution and his free speech rights. His case will also build on a 2003 U.S. Supreme Court decision that struck down a Texas law banning sodomy by charging that it was an intrusion on privacy.

We only wish to live our private lives according to our beliefs, Brown said in a statement provided to the New York Times by his attorney.

That strategy could cause some unease among same-sex marriage supporters, who have to fend off arguments that same-sex marriage will send society down a slippery slope of legalizing taboo acts like bigamy and bestiality.

The Mormon Church has formally disavowed the practice of polygamy, a source of intense conflict with the United States government during Mormonism's early days in the 19th century, but fundamentalist branches of Mormonism continue to practice it.