Polygamy was once a cherished practice in the Mormon church (who call themselves the Latter Day Saints or LDS). In order for Utah to become a state, however, and I think for some other legal reasons, the practice was "officially" banned by the LDS church a long time ago. That hasn't stopped some, though, as every now and then a polygamist is prosecuted and gets 15 seconds of fame on t.v. The latest, if I recall, was some guy named (I think) Tom Green. He lived with a handful of wives and a few dozen children. My libertarian side says that the government has no business regulating marriages, and if a group of consenting adults wants to have a polygamous relationship then they should be free to do so. As long as no harm comes to any of the children.
Well, there exists on the border of Utah and Arizona two small communities under nearly complete control from a group calling themselves the FLDS (Fundamentalist LDS) Church. Their leader, in true cult style, has absolute authority over everyone and everything that happens in these towns. He receives "revelations" from "God" and dictates who shall marry whom and when and under what circumstances. Girls younger than 18 are frequently "married" to men far older who already have at least one wife. They then take on their duty of being baby factories, some having more than one child by the time they are 18. The social pressure is so enormous on these girls that those who do "escape" usually return and those who can testify against their abusers usually back down because they don't want to send anyone in their group to jail for fear of divine retribution from "God". The group even has a "sister" community in Canada with which young girls are frequently "traded".
You'd think that the law-enforcement community would do something about this. Problem is, the law-enforcement community in this area is polygamist too! A Colorado City police officer is only just now convicted of "unlawful sex with a minor" after his teenage wife finally got the courage to testify after backing down in the past.
The officer's defense attorneys tried to argue that he should be acquitted because he was merely following deeply-held religious beliefs, or what he believed to be "God's law". "Law" which was once common throughout Utah. Even many "mainstream" Mormons who are "officially" barred from polygamy believe that polygamy will be practiced in the "afterlife".
Well the excrement may soon be hitting the proverbial fan. The leader, Warren Jeffs, of the FLDS has recently received a "revelation" from "God" saying that the erection of a monument to the failed raid of the community by Arizona officials 50 years ago is glorifying man instead of "God" and so the community will be punished. This punishment includes no priesthood meetings, no church services, no "marriages", nothing. In a time when the Utah and Arizona attorneys General are joining forces to prosecute him, many people suspect this "revelation" to be a sign that Jeffs is closing up shop and planning to flee the country.
Oh, and I forgot to mention that there is an armed vigilante force sworn to protect Jeffs and the community from any outside forces. Another testament to the dangerous power that religion holds over human minds.