Polygamy is a marriage that involves multiple spouses, instead of two. Polygamy has been practiced for centuries but has been eliminated in most modern societies. There are a few different types of polygamy. A union that involves one woman and two or more men is correctly termed polyandry, while a union involving one man and two or more women is called polygyny.
The latter arrangement is by far the most prevalent demographic. While polygamy is illegal in the United States and other countries, it is still practiced in many areas. In fact, there is a movement that goes hand in hand with the same sex marriage movement in the U.S. that hopes to include polygamy in the redefinition of marriage.
Bigamy is sometimes used interchangeably with polygamy, although they are not necessarily the same thing. Bigamy technically means having two spouses at the same time, and the term is frequently used to describe two separate marriages, often when one spouse does not know about the other. Bigamy can also refer to having two spouses in a single household, but such arrangements are generally referred to as polygamy.
The preferred term in this and similar debates is plural marriage, rather than polygamy. Within the poly culture, words like polyfidelity may also be used. The terms polygamy, polyandry, and polygyny are often seen as being anthropological in nature, and not especially effective for describing in detail the different types of poly relationships.
The concept of polygamy, specifically polygyny, tends to be a fertile issue for controversial debate. While some claim polygamy is a religious tenet, others claim it is a simple matter of choice, one which they believe should be open to all free people. However, the definition of free people often includes minor children, which leads to the other side of the argument. Those who are against polygamy, or plural marriage, believe it is an unhealthy living arrangement, due in part to headlines and news stories that reflect the most extreme cases.
Other concerns are centered on the potential for legalized polygamy to lead to an unbalanced society. Simple math leads to this conclusion. If one man marries two or more women, it may leave two or more other men with no potential mate.