The data in this report is from the Annual Social and Economic Supplement (ASEC) to the 2003 Current Population Survey (CPS). The population represented (the population universe) in the ASEC is the civilian non institutionalized population living in the United States. Members of the Armed Forces living off post or with their families on post are included if there is at least one civilian adult living in the house hold. Most of the data from the ASEC were collected in March (with some data collected in February and April), and the data was controlled to independent population estimates for March 2003. The decades long decline in the proportion of family groups with children that were married couple families leveled off during the mid 1990s, at about 68 percent from 1996 to 2003. This change reflects declining divorce rates and reduced non marital fertility, especially among teens. Between 1970 and 1996, the median age at first marriage also increased but since 1996 has been fairly stable for both men and women. Basic trends in household and family composition, living arrangements and marital status of adults, and characteristics of unmarried couple households are presented in this report. A new section is included that highlights married couple families with a stay at home parent.