Final answer:
Monogamy is the most commonly condoned form of marriage worldwide, including the inclusion of same-sex marriages. While polygamy is accepted in some cultures, it is not as widely practiced as monogamy, and in the US, polygamy is illegal. Cultural attitudes towards marriage can change, as evidenced by shifts in practices like Iceland's high rate of children born to unmarried couples.
Step-by-step explanation:
The most commonly condoned form of marriage worldwide is monogamy, which is a social system in which an individual has only one spouse at a time. This form of marriage is highly prevalent in postindustrial societies where family units are typically smaller and more mobile. The concept of monogamy also includes same-sex marriages, which have been legalized in many parts of the world, including 30 countries. In contrast, polygamy, the marriage system where an individual has more than one spouse at a time, is accepted in various cultures, particularly in northern Africa and east Asia, although it is less commonly practiced than monogamy.
In specific regions, such as the Central African Republic and Cameroon, both monogamous and polygamous marriages are practiced, with polygamous unions often sanctioned by law. Serial monogamy, which involves a person having a series of monogamous marriages over their lifetime, is increasing in Western societies and illustrates another aspect of the monogamous marriage system, with high rates of divorce and remarriage.
In the United States, monogamy is the norm, and polygamy is illegal. However, perspectives on polygamy vary, with some populations viewing it as morally acceptable, though it generally remains among the least accepted behaviors. Cultural attitudes towards marriage, including the practice of monogamy, are subject to change and adaptation over time, as seen in places like Iceland, where a significant number of children are born to unmarried, committed couples, reflecting a shift in familial structures and the fluid nature of marriage concepts in urban Western societies.