In the United States, being born to an unmarried mother is more likely to lead to less favorable outcomes than is being born to a married mother. In the U.S., births to unmarried women (i.e., nonmarital births) are widespread, touching families of varying income class, race, ethnicity, and geographic area. Many analysts attribute this to changed attitudes about fertility and marriage. They find that many adult women and teenage girls no longer feel obliged to marry before, or as a consequence of, having children. During the 66-year period from 1940 to 2006, the percentage of births to unmarried women increased by a multiple of nine, from 3.8% in 1940 to 38.5% in 2006. This represented about 1.6 million children in 2006. "Nonmarital births" can be first births, second births, or higher-order births; they can precede a marriage or occur to a woman who has never married. "Nonmarital births" can occur to divorced or widowed women. Moreover, a woman with several children may have had one or more births within marriage and one or more births outside of marriage. Many of the children born outside of marriage are raised by a single parent (who may or may not have a "significant other"). Parents and family life are the foundation that influences a child's well-being throughout the child's development and into adulthood. The family also is the economic unit that obtains and manages the resources that meet a child's basic needs while also playing an instrumental role in stimulating the child's cognitive, social, and emotional development. Children born outside of marriage often are raised solely by their mothers, but sometimes live in other types of family situations. Some are raised solely by their fathers, some are raised by both biological parents who are not married to each other (i.e., cohabiting). Others may be raised by a mother who is living with a male partner. Still others may be living with a mother who is divorced from someone other than their father. Additionally, some may be living with a mother whose husband died (i.e., the mother is a widow but the child was not fathered by the deceased husband). Although most children who grow up in mother-only families, father-only families, step-parent families, or families in which the mother is cohabiting with a male partner become well-adjusted, productive adults, a large body of research indicates that children who grow up with only one biological parent in the home are more likely to be financially worse off and have worse socioeconomic outcomes (even after income differences are taken into account) compared to children who grow up with both biological parents in the home. To emphasize, this research indicates that all family situations in which both biological parents are not living together (regardless of whether the mother is divorced, separated, widowed, or was never married) are more likely to result in less favorable outcomes for children than a family situation in which the child is living in a household with both biological parents. It is also noteworthy that some researchers conclude that even among children living with both biological parents, living with married parents generally results in better outcomes for children than living with cohabiting parents mainly because marriage is a more stable and longer lasting situation than cohabitation. The federal concern about nonmarital childbearing centers on its costs via claims on public assistance. These federal costs primarily reflect the fact that many of these "nonmarital children" are raised in single-parent families that are financially disadvantaged. Federal concern also arises because of the aforementioned research indicating that children living in single-parent families are more likely to face negative outcomes (financially, socially, and emotionally) than children who grow up with both of their biological parents in the home. As mentioned earlier, many children born outside of marriage are raised in single-parent families. This report analyzes the trends in nonmarital childbearing in the U.S., discusses some of the characteristics of unwed mothers, addresses some issues involving the fathers of children born outside of marriage, covers many of the reasons for nonmarital childbearing, examines the impact of nonmarital births on families and on the nation, and presents the public policy interventions that have been used to prevent nonmarital births or alleviate some of the problems that are associated with nonmarital childbearing. This report concludes with commentary on public policy interventions—healthy marriage programs, responsible fatherhood programs, and teen pregnancy prevention strategies—that may receive renewed attention and debate in the 111 th Congress. Nonmarital childbearing sometimes results in negative outcomes for children mainly because children born outside of marriage are generally not raised by both of their biological parents but rather by single mothers. (Children living in a household maintained by a never-married mother are among the poorest population groups in the U.S.) Even in cases in which cohabiting parents start off raising their children together, it is often of short duration. This section presents some of the major findings of the report. After stabilizing in the 1990s, nonmarital births are again increasing. In 2006, 38.5% of all births were nonmarital births. This surpasses the percentage in 1960 that prompted some policymakers to claim that the black family was disintegrating because a large share of nonmarital births were to black women. In 2006, 70.7% of African American births were nonmarital births compared with 64.6% of American Indian births, 49.9% of Hispanic births, 26.6% of white births, and 16.3% of Asian births. Nonmarital births can be first births, second births, or higher-order births; they can precede a marriage or occur to a woman who has never married. Nonmarital births can occur to divorced or widowed women. Moreover, a woman with several children may have had one or more births within marriage and one or more births outside of marriage. After declining for 14 straight years, all teen births increased in 2006. Contrary to public perception, women in their early twenties, not teens, have the highest percentage of births outside of marriage. In 2005, women ages 20 through 24 accounted for 38% of the 1.5 million nonmarital births. The comparable statistic for females under age 20 was 23%. However, many women who have nonmarital births in their twenties were also teen moms. Births to teenagers are an important component of nonmarital births because more than 80% of births to teenagers are nonmarital births. Although women have been postponing marriage, women of all ages do not view marriage as a requirement for sexual activity. With the longer time span between the onset of sexual activity and marriage, the trend of high numbers of nonmarital births may/could continue. Although nonmarital births are increasing, many more children than in previous decades live with both biological parents in cohabiting situations for some period of time. According to analysts, marriage is considered a better option for children than cohabitation because marriage is more stable (i.e., lasts longer) than cohabiting situations. Growing up in a single-parent family is one of many factors that put children at risk of less favorable outcomes. The economic, social, psychological, and emotional costs associated with children with absent noncustodial parents are significant. Nevertheless, most children who grow up in single-parent families become productive adults. Children living in a single-parent home are more likely to do poorly in school, have emotional and behavioral problems, become teenage parents, and have poverty-level income (as children and adults) compared to children living with married biological parents. In 2007, 67.8% of the 73.7 million U.S. children (under age 18) lived with both of their married parents, 2.9% lived with both parents who were not married, 17.9% lived with their mother, and 2.6% lived with their father. The advent of multiple relationships that produce children adds complexity to the problem. These relationships, often referred to as multiple partner fertility (i.e., when mothers and fathers have had children with more than one partner), generally complicate the family situation of children. Compared to women without nonmarital children, women with children who were born outside of marriage are less like to marry; if they do marry, their spouses are more likely to be economically disadvantaged. Demographically, without nonmarital births, the U.S. would be far below population replacement levels. Having the birth rate reach the replacement rate is generally considered desirable by demographers and sociologists because it means a country is producing enough young people to replace and support aging workers without population growth being so high that it taxes national resources. Nonmarital births are expected to increase over time because of a projected population shift toward more minorities. The Census Bureau projects that by 2050, 54% of the U.S. population will consist of minority groups (i.e., Hispanics, blacks, Indians, and Asians). Minorities, now roughly one-third of the U.S. population, are expected to become the majority in 2042, with the nation projected to be 54% minority in 2050. By 2023, minorities will represent more than half of all children. The Hispanic population is projected to nearly triple, and its share of the nation's total population is projected to double, from 15% to 30%. Thus, nearly one in three U.S. residents will be Hispanic. In 2005, 48% of Hispanic births were nonmarital births. In this report, births to unmarried women are termed nonmarital births. Data on nonmarital births are usually expressed by three measures: the number of nonmarital births, the percent of births that are nonmarital, and the rate of nonmarital births per 1,000 unmarried women.