In general, polygamy is legal in about 25% of countries in the form of polygyny, the practice of one husband having two or more concurrent wives. Legal polyandry, the practice of one wife having two or more concurrent husbands, is much less common. Legal group marriage, the practice of concurrent marriages amongst multiple participants often with multiple participants of each gender, is also extremely uncommon. Some countries legally allow polygyny only among their Muslim population. A majority of the world's countries and nearly all of the world's developed nations do not permit polygamy, and there have been calls for the abolition of polygamy in many developing countries.wikipedia
