Marriage plays a fundamental role in civil society because it is characterized by sexual complementarity, monogamy, exclusivity, and permanence. These marriage norms encourage men and women to commit permanently and exclusively to each other and take responsibility for their children.
In recent decades, a revisionist view of marriage has eroded these norms. No-fault divorce was the first major trend to undermine a strong marriage culture. Now the effort to redefine marriage away from male-female complementarity has gone even further in abandoning the central characteristics of the institution. But if the law redefines marriage to say the male-female aspect is arbitrary, what principle will be left to retain monogamy, sexual exclusivity, or the expectation of permanency? Such developments will have high social costs.