Americans typically equate marriage with monogamy, when someone is married to only one person at a time. In many countries and cultures around the world, however, having one spouse is not the only form of marriage. In a majority of cultures (78 percent, actually), polygamy, or being married to more than one person at a time, is accepted, with most polygamous societies existing in northern Africa and east Asia. Instances of polygamy are almost exclusively in the form of polygyny. Polygyny refers to a man being married to more than one woman at the same time. The reverse, when a woman is married to more than one man at the same time, is called polyandry. It is far less common and only occurs in about one percent of the world’s cultures. The reasons for the overwhelming prevalence of polygamous societies are varied but they often include issues of population growth, religious ideologies, and social status.