evidence: Background: In 2009, approximately 410,000 teens aged 15--19 years gave birth in the United States, and the teen birth rate remains higher than in other developed countries. [...] Despite declines since 1991 (1), the teen birth rate in the United States remains as much as nine times higher as in other developed countries (2),* and significant racial/ethnic and geographic disparities exist in the United States (3,4). Compared with births to adult women, births to teens are at greater risk for low birth weight, preterm birth, and death in infancy (5,6). Teen childbearing also perpetuates a cycle of disadvantage; teen mothers are less likely to finish high school, and their children are more likely to have low school achievement, drop out of high school, and give birth themselves as teens (7,8). Each year, teen childbearing costs the United States approximately $6 billion in lost tax revenue and nearly $3 billion in public expenditures. However, these costs are $6.7 billion lower than they would have been had teen childbearing not decreased (9). [...] * By comparison, the U.S. teen birth rate is nearly one and a half times higher than the teen birth rate in the United Kingdom, which has the highest teen birth rate in western Europe. The U.S. rate is nearly three times higher than the teen birth rate in Canada and six to nine times higher than the teen birth rates in Denmark, the Netherlands, Sweden, and Switzerland (2).