Recently, child welfare officials allege in court documents that the Fundamentalist Church of Jesus Christ of Latter Day Saints outside of Eldorado, Texas, was "rife with sexual abuse, with girls spiritually married to much older men as soon as they reached puberty and boys were groomed to perpetuate the cycle [source: AP]. " In 1997, Warren Jeffs, the former church leader, was prosecuted and found guilty on two charges of rape by accomplice.

Two members of the polygamist Fundamentalist Church of Jesus Christ of Latter Day Saints
AP Photo/Tony Gutierrez
Two members of the polygamist Fundamentalist Church of Jesus Christ of Latter Day Saints in San Angelo, Texas, Wednesday, April 9, 2008.
On the popular HBO drama "Big Love," Bill Paxton plays a man with three wives who live next door to each other and share a backyard. So polygamy isn't just on fictional TV, but are any of these portrayals accurate?

Today, most Americans think of monogamy as the "normal" form of marriage. But as it turns out, strictly monogamous practices are in the minority. In fact, cultures that practice some form of polygamy outnumber monogamous cultures by the hundreds [ref]. Some critics suggest that the Western practice of frequent divorce and remarrying represents a form of serial polygamy, though most anthropologists consider it serial monogamy -- no one gets married to more than one person at one time.

More on Polyandry
While polyandry is rare, societies that allow both multiple husbands and multiple wives is even rarer. The Amazon Zoe tribe is a notable example of this practice.
The Nyinba people of Nepal practice fraternal polyandry. Polyandry is a form of polygamy in which one woman has multiple husbands. In Nyinbian culture, when a woman marries a man, she marries all of his brothers, too. All of the brothers have equal sexual access to the wife, and the entire family cares for the children, although the family may recognize individual brothers as the specific father of a given child [ref]. This kind of marriage structure concentrates the wealth and resources of all the brothers into one family, and also concentrates their parents' land and wealth.

Polygyny, on the other hand, rewards males who have access to greater wealth and resources than others. It takes a lot of work and money to support a large number of wives and the children they produce. In biological terms, such a man is an excellent choice for reproducing and passing his genes on to the next generation, which could be expected to be similarly successful. A man can father many children in a short period, while a woman is limited to one pregnancy every nine months. If a successful man has many wives, he can pass on his genes more often. This is also an advantage in societies where rapid and frequent reproduction is vital for survival. Early Jewish doctrine encouraged polygyny because Jews were a minority and needed to increase their numbers rapidly. Some orthodox Jewish sects advocate polygyny today, and some scholars believe that the Talmud contains passages suggesting tolerance or even encouragement of polygyny.

Islamic tradition addresses polygamy directly. The Koran states that a man is allowed up to four wives, but only if he can support them and treat them all equally. Many Islamic societies continue to allow polygamy, but usually only the most affluent men can afford multiple wives. Westernization has led many younger Muslims to view polygamy as old-fashioned.

In Vietnam, polygamy is not legal, but there's a practical reason for its practice -- decades of war has left the male population severely depleted. Polygamy was also common in China before Confucianism, which supported the practice, fell out of favor. Many African tribes, Native American tribes and pre-Christian Celts practiced polygamy, often without the conservative restraints on the sexual aspects of it that characterize Mormon polygamy [ref].

Next, we'll look at the Mormons, polygamy and the United States legal system.

Polyamory, Bigamy and "Swingers"
Polygamy is often confused with polyamory and bigamy. Bigamy occurs when one man illegally marries more than one woman. He might marry a second wife before his divorce is complete, for example. In rare cases, men have carried on double lives, marrying two women and supporting two families, with neither wife knowing about the other. Practicing polygamy in a country with laws that forbid it is technically bigamy.

Polyamory is the concept of being in love with more than one person at one time. Polygamists practice polyamory, but polyamorists don't necessarily practice polygamy. They may have living arrangements in which multiple adults form one family, share economic burdens, care for children and share sexual access with one another. However, they do not usually attempt to form a legal marriage. The line between a polyamorous family and a polygamist family is a fine one. Although broad generalizations always have exceptions, polyamorists tend to have communal, liberal views, while polygamists generally come from conservative religious backgrounds.

Swingers are married people who openly engage in sex with people other than their spouses. They don't generally form lasting relationships beyond friendships, nor do they form family structures: the focus is on sex alone.