As a companion to Elizabeth’s post just below, here is John Witte in the WaPo on monogamy/polygamy and on the goods of marriage:
Given these four factors, nature has strongly inclined rational human persons to develop enduring and exclusive sexual relationships, called marriages, as the best form and forum of sexual bonding and reproductive success. Faithful and healthy monogamous marriages are designed to provide for the sexual needs and desires of a husband and wife. They ensure that both fathers and mothers are certain that a baby born to them is theirs. They ensure that husband and wife will together care for, nurture, and educate their children until they mature. And they deter both spouses from destructive sexual behavior outside the home.
Polygamy might ensure paternal certainty, but only at ample cost. Social science studies of polygamous families in Africa and Asia, and in isolated Fundamentalist Mormon communities in North America have documented these costs. While a polygamous man usually has his sexual needs met, his multiple wives often do not, producing rivalry and discord in the home. While a polygamous father may know who his children are, his children have to work hard to get his attention, affection, and resources which are dissipated over multiple wives and children. While polygamy might seem to contain extramarital sex better than monogamy, the opposite is often true. A polygamous man, not schooled by monogamous habits, will always be tempted to add another attractive woman to his harem. A co-wife, once pushed aside by another, will be sorely tempted to test her neighbor’s or servant’s bed, unless threatened with grave retribution. And single men, with fewer chances to marry, will resort more readily to prostitution, seduction, and other destructive sexual behavior.
Witte is a long time friend and, in my view, a terrific scholar of issues related to marriage, law, and religion.