Polygamy (from Late Greek πολυγαμία (polugamía) "state of marriage to many spouses") is the practice of marrying multiple spouses. When a man is married to more than one wife at the same time, sociologists call this polygyny. When a woman is married to more than one husband at a time, it is called polyandry. Scientific studies classify the human mating system as primarily monogamous, with the cultural practice of polygamy in the minority, based both on surveys of world populations, and on characteristics of human reproductive physiology.