The movement for same-sex marriage has triggered an unprecedented crisis in the social norms and laws governing marriage. All great civilizations have sought to unite, in the institution of marriage, the goods of sexual intimacy, childbearing and childrearing, and life-long love between adults. But the last five decades have witnessed the erosion of marriage as a public institution in the developed world. The separation of the goods previously united in marriage has led thoughtful people to question why marriage should be denied to homosexuals.