verview Despite a 22 percent decline in the rate of teenagers giving birth in the United States since 1991, adolescent reproductive health remains a pressing social issue. The U.S. teen birth rate, while declining, is still one of the highest among developed nations. For example, the teen birth rate in the U.S. in the mid-1990s was more than double the rate for Canada and more than four times the rate in Germany. Moreover, sexually transmitted diseases (STDs) in the United States, highest among teens and young adults, are higher than STD rates in other industrialized nations. Why does this matter? Because adolescent childbearing and STDs carry significant social costs. These costs are borne by the teenagers themselves, by society as a whole, and-perhaps most poignantly-by the children of teenage mothers, who start out life at serious disadvantage. 52 Beyond the social costs are the financial ones which are measured in the billions of dollars. In this brief, we define improved adolescent reproductive health as involving one of the following behaviors: delaying sexual initiation, reducing the frequency of sexual activity, reducing the number of sexual partners, increasing condom use and overall contraceptive use, and reducing the rate of unintended pregnancy and childbearing, as well as lowering the incidence of STDs among teenagers. To do so, in turn, requires taking a closer look at the range of factors that lead to positive reproductive health behaviors. In this context, Child Trends conducted a review of more than 150 research studies on adolescent reproductive health to identify the factors that contribute to improving adolescent reproductive health. This Research Brief highlights these and other findings from the vantage point of adolescents as individuals and within the context of their families, peers, partners, schools, and communities. In addition, we developed a What Works table (see insert) that identifies specific programs and approaches that have been found successful in improving positive reproductive health behaviors. Experimental studies that focus on reproductive health outcomes discussed in the section on policy implications, show mixed results from evaluations of sexuality education and HIV education programs, which are part of many schools' curriculums. Among programs and approaches found to be successful in improving reproductive health behaviors are those that focus on early childhood development, those that combine sexuality education for older children with positive activities, such as participating in voluntary community service and youth development programs, and those that send nurses to visit with teenage mothers with reducing the likelihood of having another child as a teen as one of their goals. This is the first in a series of Research Briefs based on a comprehensive review of adolescent development research. The American Teens series will cover reproductive health, physical health and safety, social skills, education, mental and emotional health and civic engagement as they relate t...