This article draws attention to a cultural shift in the formation of families that has been and is taking place in this country and in the developed world. Part I uses recent government data to trace the decline of marriage and the rise of cohabitation in the United States. Between 2000 and 2010, the population grew by 9.71 %, but the husband and wife households only grew by 3.7%, while the unmarried couple households grew by 41.4%. A counter-intuitive finding is that the early 21st century data show little correlation between the marriage rate and economic conditions. Because of the Supreme Court\u27s decision in Obergefell v. Hodges (2015), same-sex marriage is now universally available to same-sex couples. Part I considers the impact of ...