The polygyny with separate households is more universally prevalent. Where, on the other hand, as among many N. American tribes, two or more wives share the same household, polygyny affects the institution of matrimonial life much more deeply. Various theories have been advanced to explain the cultural endorsement of polygyny. While this theory is of historical interest, there exists no empirical support for the greater sex drive of the male, nor is there any reason to expect the male sex drive to vary from one culture to another. Women are just as naturally interested in sex, perhaps even more so.
Women can be multi- orgasmic and have a much broader range of sexual stimulation than men.
While men may seek other sexual relationships during the period of a long postpartum taboo, it is not clear why polygyny is the only possible solution to the problem, since the legitimation of sex does not depend exclusively on marriage. The problem could be alleviated by extra-marital alliances or masturbation. Polygyny maximizes the opportunities for females to marry in a society in which adult males are in short supply. The fact that the sex ratio at the same time of young adulthood is numerically balanced in some societies suggests that while a sex ratio imbalance may contribute to the development of polygyny in special cases, it is an incomplete explanation for the existence of polygyny in the majority of societies in the world. For example, plural marriage developed among the Mormons in Utah when, as in most of the western states of the United States, there was an excess of males.