The first section of this report describes the context in which America's children live, such as changes in children's family settings and living arrangements. The report indicates that although the majority of children live with two married parents, 32 percent do not. In 2003, 23 percent of children lived with only their mothers, 5 percent lived with only their fathers, and 4 percent lived with neither of their parents. Among all U.S. children 15 percent had a parent who had not received a high school diploma. In 2002, 34 percent of children under 18 years old lived in areas that did not meet one or more of the Primary National Ambient Air Quality Standards, up significantly from 19 percent in 2001. The next four sections of the report focus on indicators of economic security, health, behavior and social environment, and education. Regarding economic security, the number of children living in families with incomes below their poverty threshold increased from 11.2 million in 2001 to 11.6 million in 2002. The health of the Nation's children continues to improve in many areas; however, there have been increases in obesity, infant mortality, and low birth weight. Victimization rates for juveniles as well as violent offending rates by juveniles have declined. High school advanced course-taking rates are at the highest levels in the past 20 years. 10 figures and a summary list of measures and indicators of child well-being.