Polygamy is the practice of having two or more spouses at the same time; this includes both polygyny (the union of one man with more than one woman) and polyandry (the union of one women with more than one man).
Polygamy is condoned in the original texts of many faiths; in the Bible, there is Lamech’s marriage to Adah and Zillah in Genesis (4:23), and Joseph’s four wives (Gen 29-30), amongst others. In Judaism, most of the prophets are polygamous and Solomon is said to have had 700 wives. In Islam, the Koran tells us that after the battle of Uhud many widows were left, who were married to already married men (4:3). However, most religions now ban the practice and it is rare in Islam. In most countries, including all western ones and some Islamic ones, polygamy is illegal, although some Muslim states (such as Saudi Arabia) do allow it. Apart from these Islamic examples, polygamy does continue in some African societies but is more generally – although incorrectly – seen as a practice of Mormons.
In the 1840s, Joseph Smith, the founder of the Church of Jesus Christ of the Latter Day Saints (the proper name for the Mormon church), approved the practice of polygamy. However, statehood for Utah only came in 1896 when its leaders finally agreed to abolish polygamy in return for it and for more than a century the Mormon church has expelled those practising polygamy. It is undoubtedly true that a blind-eye policy is practiced in some remote places, but the widespread idea that polygamy is legal in Utah is entirely wrong. Whilst examples are certainly relevant, this debate should revolve around the principles concerned: it should not be a debate solely about Mormons.
It should be noted that many of the organisations in favour of polygyny – particularly, faith-based groups – are explicitly against polyandry. This topic will present the merits of both, but will consider the roots of that division.
Bramham, Daphne, The Secret Lives of Saints: Child Brides and Lost Boys in Canada's Polygamous Mormon Sect (Random House, 2008)