[Social scientific research, here only briefly summarized, discriminates between nuptial cohabitors, who have already made the commitment to marry, and non-nuptial cohabitors, who have not made that commitment. It further shows that for nuptial cohabitors their cohabitation is the first step in their becoming married, that their characteristics are more like the characteristics of married couples than singles, and that the data applicable for the 1970s and 1980s namely that those who cohabit prior to marriage and then marry have a heightened risk of divorce is no longer verified in recent cohorts. The Catholic Church needs to pay attention to this scientific data so as to develop a more discriminating pastoral approach to the phenomenon of cohabitation.]