In the United States, births to unmarried women (i.e., nonmarital births) are widespread, including families of varying income class, race, ethnicity, and geographic area. Many analysts attribute this to changed attitudes over many years 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 period from 1940 to 2008, the percentage of births to unmarried women increased from 3.8% in 1940 to 40.6% in 2008, and has remained at about 41% each subsequent year through 2013. This represented 1.6 million children in 2013 (see Table A-1 .). Although nonmarital childbearing is not a new phenomenon, the relatively recent factors associated with historically high levels of nonmarital childbearing are that women are marrying later in life and more couples are cohabiting. Other factors include decreased childbearing of married couples, increased marital dissolution, increased sexual activity outside of marriage, participation in risky behaviors that often lead to sex, improper use of contraceptive methods, and lack of marriageable partners. "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. A majority of nonmarital births now are to cohabiting parents. Between 2006 and 2010, 58% of nonmarital births were to cohabiting parents, compared with 40% in 2002. Unlike in years past, although most of the children born outside of marriage are raised by a single parent (who may or may not have a "significant other"), many, especially during their infancy, live with both of their biological parents who are not married to each 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. 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. However, 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. In 2012, 70% of the children under age 18 who lived with both of their married parents were in households with incomes at least 200% above the poverty level, whereas 44%-46% of children who lived with their mother only, two unmarried parents, or no parents were living below the poverty level. The federal concern about nonmarital childbearing generally 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 United States, discusses some of the characteristics of unwed mothers, addresses some issues involving the fathers of children born outside of marriage, and offers some concluding remarks. Declining marriage rates, increased childbearing among unmarried women, an increased number of unmarried women in the childbearing ages (i.e., 15-44), and decreased childbearing among married women have contributed to the rising share of children being born to unwed women. Many social science analysts attribute the increase in nonmarital births to the decades-long decline of "shotgun marriages," rather than to an increased incidence of nonmarital conceptions. They contend that when the social pressure to get married once pregnancy became obvious lessened, the likelihood that women would marry between conception and birth decreased substantially. The entry of more and more women into the paid labor force also made childbearing outside of marriage more economically feasible. Through the 1960s, most Americans believed that parents should stay in an unhappy marriage for the sake of the children. By the 1970s, this view was not as prominent. Divorce and not getting married to the father of a child—which were generally considered not to be in the best interest of the child—became more acceptable if they resulted in the happiness of the adult. Thus, many observers and analysts agree that marriage is now more likely to be viewed through a framework of adult fulfillment rather than through a framework of child well-being. On average, those who marry are marrying later. The age at which persons in the United States first marry has increased significantly since the 1950s. The typical age of first marriage in the United States is currently 27 for women and 29 for men. It is now not uncommon for first births to precede first marriage. The difference between the average age of first intercourse (17) and the age at first marriage (25) for women is eight years. For the majority of adult women, living without a spouse does not mean living without sex, nor in many cases does it mean living without having children. The report entitled "Knot Yet: The Benefits and Costs of Delayed Marriage in America," indicates that "at the age of 24, 44 percent of women have had a baby, while only 38 percent have married; by the time they turn 30, about two-thirds of American women have had a baby, typically out of wedlock." Cohabitation has now become a common method of family formation. Based on data covering the period 2006-2010, the first union of women (ages 15 through 44) was more likely to be cohabitation than marriage. According to the survey data, 48% of the women interviewed in 2006 through 2010 cohabited as a first union as compared to 23% who married as a first union (29% were single/unattached). The same survey data also indicated that by age 30, 74% of women had lived with a male partner without being married to him. According to a report entitled Household Change in the U nited States : One of the major trends driving the growth in nonfamily households with two or more people is the increase in cohabitation among unmarried adults. In 1970, less than 1 percent of all households included unmarried couples, yet by 2010, this share had increased to nearly 7 percent. This share may seem too low given that the majority of young adults today cohabit at some point, and that more than half of recent marriages were preceded by cohabitation. This apparent anomaly is due to the fact that most cohabiting unions in the United States don't last long, either transitioning to marriage or ending within a few years. Therefore, the number of unmarried-partner households counted at one point in time, such as in the 2010 Census, is relatively small. The long‐term trend toward nonmarital births may be attributed, in part, to an increase in cohabiting unions and in births within such relationships. According to several studies, a majority of nonmarital births now occur to cohabiting parents. During the period 2006-2010, it was estimated that 58% of nonmarital births were to cohabiting parents. Recent data indicate that the notion that unmarried births equal mother-only families is no longer fully correct. The decline in the percentage of births to married women has in large measure been in tandem with the increase in births to parents who are living together but who are not married (in cohabiting relationships). Some children live with cohabiting couples who are either their own unmarried parents or a biological parent and a live-in partner. The Census Bureau data do not indicate the number of newborns by the marital status of their parents, but data are available for children under age one by parents' marital status. In 2012, 16.7% of the 3.9 million children under age one were living with their biological mothers who had never married, 1.4% were living with their biological fathers who had never married, and 12.4% were living with both biological parents who were not married to each other (67.6% of those children under age one were living with both of their biological parents who were married to each other). Another view of the data indicates that of the 1.2 million children under age one who were living with parents who had never married or were not married to each other, 55.6% lived with their mothers, 4.6% lived with their fathers, and 39.8% lived with both parents. Some analysts contend that the increase in nonmarital childbearing could be seen as less of an issue if viewed through a framework that portrays out-of-wedlock births as babies born to cohabiting couples rather than to "single" women. Others point out that cohabitation is a complex phenomenon that has an array of meanings. Some view it as a precursor to marriage while others view it as an alternative to marriage. According to one study: cohabitation is a continuous rather than a dichotomous variable. At both ends of the continuum, there is substantial agreement across measures about who is (not) cohabiting. In the middle of the continuum, however, there is considerable ambiguity, with as much as 15% of couples reporting part-time cohabitation. How we classify this group will affect estimates of the prevalence of cohabitation, especially among African Americans, and may impact the characteristics and outcomes of cohabitors. It is estimated that two-fifths of all children in the United States will live in a cohabiting household by age 12. Cohabiting relationships are generally considered less stable than marriages. According to several sources, cohabiting relationships are fragile and relatively short in duration. Survey data covering the period 2006-2010 indicated that the length (i.e., median duration) of first premarital cohabitation (among women ages 15 through 44) was a little less than two years (22 months). The median length of marriage before divorce was eight years. 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. The number of nonmarital births provides the total count of babies who are born to women (including adolescents) who are not married. The percent of all births that are nonmarital is the number of all nonmarital births divided by all births (both nonmarital births and marital births). The nonmarital birth rate is defined as the number of nonmarital births (to females of any age) per 1,000 unmarried women ages 15-44. The number of nonmarital births reached a record high in 2008 with 1,726,566 births to unmarried women. As mentioned above, the number of births to unmarried women has generally increased over the years, with some downward fluctuations. Nonmarital births rose 17-fold from 1940-2013, from 89,500 in 1940 to 1,605,643 in 2013. (See Figure 1 and Table A-1 .) The average annual increase in nonmarital births has slowed substantially from earlier decades. The average annual increase in nonmarital births was 4.9% from 1940-1949; 5.6% from 1950-1959; 6.1% from 1960-1969; 5.0% from 1970-1979; and 6.4% from 1980-1989. The 1990s showed a marked slowing of nonmarital births, dropping from an average increase of 6.4% a year in the 1980s to an average of 1.2% a year in the 1990s. Nonmarital births increased an average of 2.6% per year from 2000-2009. During the four years from 2010 through 2013, nonmarital births decreased , on average, 0.2% per year. In 2013, there were 1.6 million nonmarital births. The percent of births to unmarried women increased substantially during the period from 1940-2013 (see Figure 2 and Table A-1 ). (However, from 1994-2000, there was almost no change in this measure.) In 1940, 3.8% of all U.S. births were to unmarried women. By 2009, a record 41.0% of all U.S. births were to unmarried women. In 2013, the percent of births to unmarried women had decreased slightly to 40.6%. The birth rate is the total number of births per 1,000 of a population each year. The nonmarital birth rate provides a measure of the likelihood that an unmarried woman will give birth in a given year. The nonmarital birth rate is defined as the number of births to unmarried women (regardless of the age of the mother) per 1,000 unmarried women ages 15 through 44. The nonmarital birth rate reflects both overall fertility and the percentage of births that are nonmarital. The birth rate for unmarried women increased dramatically during the 1940-2013 period, with many upward and downward fluctuations. (However, during the years 1995-2002, the nonmarital birth rate remained virtually unchanged. ) The nonmarital birth rate increased from 7.1 births per 1,000 unmarried women ages 15 through 44 in 1940 to a record high of 51.8 births per 1,000 unmarried women ages 15 through 44 in 2007 and 2008 (a six-fold increase). In 2013, the nonmarital birth rate was 44.8 births per 1,000 unmarried women ages 15 through 44. (See Figure 3 and Table A-1 .) The composition of nonmarital births reflects the size of the population of women of childbearing age, overall fertility, and the percent of births that are nonmarital. The share of unmarried births for a group can increase, for example, through a decline in the marital birth rate, an increase in the nonmarital birth rate, or both. In addition, the share of nonmarital births for a group can increase through a shift in the proportion of women of childbearing age who are not married. Teen marriage and birth patterns have shifted from a general trend of marrying before pregnancy, to marrying as a result of pregnancy, to becoming pregnant and not marrying. Early nonmarital childbearing remains an important issue, especially in the United States, because young first-time mothers are more likely to have their births outside of marriage than within marriage, and because women who have a nonmarital first birth are more likely to have all subsequent births outside of marriage, although often in cohabiting unions. Until recently, a commonly held view was that teenagers had the highest share of nonmarital births. However, as Figure 4 shows, women in their 20s had the greatest share of nonmarital births. In 2013, 15% of the 1.6 million nonmarital births in the U.S. were to teenagers (under age 20), 37% were to women ages 20 through 24, 25% were to women ages 25 through 29, 15% were to women ages 30 through 34, 6% were to women ages 35 through 39, and 2% were to women ages 40 and above. The largest share of children born to unmarried women are white; however, minority children, particularly black children and Hispanic children, are overrepresented. Of the 1.6 million children who were born outside of marriage in 2013, 39% were white (whites constituted 64% of the U.S. population), 26% were black (blacks constituted 13% of the population), 2% were American Indian/Alaskan Native (American Indians or Alaskan Natives constituted 1% of the population), 3% were Asian or Pacific Islander (Asians or Pacific Islanders constituted 6% of the population), and 30% were Hispanic (Hispanics constituted 17% of the population). Moreover, the age and nonmarital birth data for 1990 and 2013 displayed in Figure 5 show that for all age groups a growing share of women are having nonmarital births. This section discusses some of the characteristics of unmarried mothers. Some of the highlights include the following: black women are more likely to have children outside of marriage than other racial or ethnic groups; it is not teenagers but rather women in their early twenties who have the highest percentage of births outside of marriage; single motherhood is more common among women with less education than among well-educated women; a substantial share of nonmarital births (44%) were to women who had already given birth to one or more children; a significant number of unwed mothers are in cohabiting relationships; and women who have a nonmarital birth are less likely than other women to eventually marry. The rate at which unmarried women have children varies dramatically by race and ethnicity. As mentioned earlier, in 2013 the nonmarital birth rate for all U.S. women was 44.8 births per 1,000 unmarried women (in 2012, it was 45.3). In 2012, Hispanic women had the highest nonmarital birth rate at 72.6 births per 1,000 unmarried Hispanic women. The nonmarital birth rate in 2012 was 62.6 for black women, 32.1 for non-Hispanic white women, and 22.9 for Asian or Pacific Islander women. In 2013, 40.6% of all U.S. births were to unmarried women. In that year, 71.4% of births to black women were nonmarital births. The percentage of nonmarital births for American Indians or Alaska Natives was 66.4%. The nonmarital birth percentage was 53.2% for Hispanic women, 29.3% for non-Hispanic white women, and 17.0% for Asian or Pacific Islander women. (See Table 1 .) In 2013, the percentage of nonmarital births to black women (71%) was more than three times the 22% level of the early 1960s that so alarmed Daniel Patrick Moynihan, then President Johnson's Assistant Secretary of Labor. Moynihan addressed the issue in a report called "The Negro Family: The Case for National Action." One theory that attempts to explain the disproportionate share of nonmarital births to black women hypothesizes that the universe of males (ages 15 and above) who are unmarried is disproportionately lower for blacks. For example, in 2012 there were 75 black unmarried males for every 100 black unmarried females; 88 white non-Hispanic unmarried males for every 100 white non-Hispanic unmarried females; 90 Asian unmarried males for every 100 Asian unmarried females; and 105 Hispanic unmarried males for every 100 Hispanic unmarried females. Supporters of this theory argue that if the universe of possible marriage partners is reduced even further to desirable marriage partners (e.g., heterosexual men, men with steady jobs, men without a criminal record, and men with a similar educational background), the black "male shortage" is drastically increased. In recent years, most teenagers who give birth are not married. For example, 13% of the 419,535 babies born to teens (ages 15 through 19) in 1950 were born to females who were not married. By 2013, 89% of the 274,641 babies born to teens (ages 15 through 19) were born to unwed teens. (See Table 1 .) There are two reasons for this phenomenon. The first is that marriage in the teen years, which was not uncommon in the 1950s, has become quite rare. The second is that this general trend of marriage postponement has extended to pregnant teens as well. In contrast to the days of the "shotgun marriage," very few teens who become pregnant nowadays marry before their baby is born. One of the factors that causes economic disadvantage, especially among unmarried mothers, is low educational attainment. Single motherhood has always been more common among women with less education than among well-educated women. In 2011, among unmarried women (ages 15 to 50) who had a child in the last year, those with less education had higher percentages of nonmarital births. For instance, among those who had not completed high school, 57% had a nonmarital birth. In contrast, among those who had a bachelor's degree or more, 9% had a nonmarital birth. An examination of never-married mothers shows that in 2012, 45.5% of never-married mother families (with children under age 18) had income below the poverty level. With respect to the various income categories, 23.9% of never-married mother families had income below $10,000, 43.3% had income below $20,000, and 80.2% had income below $50,000; and 19.8% had income above $50,000. Some studies have found that a woman is most likely to have a second birth while in the same type of situation (single, cohabiting, or married) as she was in for the first birth. The public perception is that nonmarital births are first births. The reality is that in recent years fewer than half of all nonmarital births were first births. According to a Child Trends report, over 50% of nonmarital births were second- or higher-order births. In 2013, of the one-parent unmarried family groups maintained by a never-married mother, 41.5% had more than one child. Several studies indicate that nonmarital childbearing is associated with reduced rates of marriage. A study based on retrospective life histories found that girls who had a nonmarital birth at age 17 were 69% more likely to have never married by age 35 than 17-year old girls who did not have a nonmarital birth (i.e., 24% vs. 14%). Women who had a nonmarital birth at ages 20 to 24 were more than twice as likely not to be married at age 35 than women who did not have a nonmarital birth at ages 20 to 24 (i.e., 38% vs. 19%). The reported implication of these findings is that there probably is a causal relationship between nonmarital childbearing and subsequent marriage. Another study points out the racial differences associated with the eventual marriage of many women who had a nonmarital birth. The study found that white women were more likely to be married than their minority counterparts. Some 82% of white women, 62% of Hispanics, and 59% of blacks who had a nonmarital first birth had married by age 40; the corresponding proportions among those who avoided nonmarital childbearing were 89%, 93%, and 76%, respectively. By some estimates, having a child outside of marriage decreases a woman's chances of marrying by 30% in any given year. Even when they do marry, women who have had a nonmarital birth generally are less likely to stay married. Analysis of data from the 2002 National Survey of Family Growth indicates that women ages 25 to 44 who had their first child before marriage and later got married are half as likely to stay married as women who did not have a nonmarital birth (42% compared to 82%). This section highlights several demographic factors associated with the fathers of children born outside of marriage. It also discusses the importance of establishing paternity for children born outside of marriage. It has been pointed out that fathers are far too often left out of discussions about nonmarital childbearing. It goes without saying that fathers are an integral factor in nonmarital childbearing. It appears that one result of the so-called sexual revolution was that many men increasingly believed that women could and should control their fertility via contraception and abortion. As a result, many men have become less willing to marry the women they impregnate. There are myriad reasons why so many children live in homes without their fathers. Some reasons are related to choices people make about fertility, marriage, and cohabitation. But others are the result of unexpected events, such as illness, or incarceration. Some noncustodial fathers are active in the lives of their children, whereas others are either unable or unwilling to be involved in their children's lives. Whatever the reason, a father's absence from the home results in social, psychological, emotional, and financial costs to children and economic costs to the nation. A 2008 report maintains that the federal government spends about $99.8 billion per year in providing financial and other support (via 14 federal social welfare programs) to father-absent families. This section of the report discusses the race and ethnicity of fathers to children born outside of marriage, age of fathers, educational attainment of fathers, and the importance of establishing paternity for children born outside of marriage. One of the prominent, but perhaps not unexpected, findings related to fathers and nonmarital births is that when older men have sexual relationships with young women it often results in nonmarital births. Data from the Fragile Families and Child Well-Being study indicate that 18% of white men, 44% of black men, and 35% of Hispanic men were unmarried at the time of their first child's birth. According to the 2002 National Survey of Family Growth, 33% of unmarried Hispanic men and 33% of unmarried non-Hispanic black men have had a biological child, compared with 19% of unmarried non-Hispanic white men. In the United States, it is not unusual for a man to be several years older than his female partner. Some data indicate that the man is three or more years older than the woman in almost 4 in 10 relationships today. However, such age differences often have adverse consequences for young women. Several studies have found that the unequal power dynamic that is often present in relationships between teenage girls and older men is more likely to lead to sexual contact not wanted by the female, less frequent use of contraceptives, and a greater incidence of sexually transmitted diseases (STDs) among the adolescent females. According to a couple of older studies, a significant share of teenagers in relationships with older men have children outside of marriage. According to one study, about 20% of births to unmarried, teenage girls are attributed to men at least five years older than the mother. According to another report, unmarried teenagers younger than 18 were especially likely to become pregnant when involved with an older partner: 69% of those whose partner was six or more years older became pregnant, compared with 23% of those whose partner was three to five years older and 17% of those whose partner was no more than two years older. Data from the Fragile Families and Child Well-Being study indicate that at the time of their first child's birth, 37% of unwed fathers had less than a high school education, 39% had a high school diploma, 20% had some college, and 4% had a B.A. degree or more. Paternity is presumed if a child is conceived within marriage. In other words, the husband is presumed to be the father of a child born to his wife. In cases in which the child is born outside of marriage, paternity can be voluntarily acknowledged or it can be contested. It would be contested in cases in which (1) the mother does not want to establish paternity, thereby forcing the father to take his case to court to assert his rights, (2) the biological father does not want to pay child support and denies paternity to delay establishment of a child support order, or (3) the alleged father has genuine doubt about his paternity. If paternity is contested it is generally resolved through either an administrative process or a judicial proceeding. A child born outside of marriage has a biological father but not necessarily a legal father. Paternity establishment refers to the legal determination of fatherhood for a child. In 2013, 40.6% of children born in the United States were born to unmarried women. Data from the federal Office of Child Support Enforcement (OCSE) indicate that in 2013 the total number of children in the Child Support Enforcement (CSE) caseload who were born outside of marriage amounted to about 11 million. Paternity has been established or acknowledged for about 9.7 million (88%) of these children (1.6 million were established or acknowledged during FY2013). Most of the children in the CSE caseload without a legally identified father are primarily older children (not newborns). Paternity establishment is not an end in itself, but rather a prerequisite to obtaining ongoing economic support (i.e., child support) from the other (noncustodial) parent. Once paternity is established legally (through a legal proceeding, an administrative process, or voluntary acknowledgment), a child gains legal rights and privileges. Among these may be rights to inheritance, the father's medical and life insurance benefits, and social security and possibly veterans' benefits. It also may be important for the health of the child for doctors to have knowledge of the father's medical history. The child also may have a chance to develop a relationship with the father and to develop a sense of identity and connection to the "other half" of his or her family. The public policy interest in paternity establishment is based in part on the dramatic increase in nonmarital births over the last several decades and the economic status of single mothers and their children. The poorest demographic group in the United States consists of children in single-parent families. Paternity establishment generally is seen as a means to promote the social goals of (1) providing for the basic financial support of all minor children regardless of the marital status of their parents, (2) ensuring equity in assessing parental liability for the financial support of their children, and (3) promoting responsibility for the consequences of one's actions. Many observers maintain that the social, psychological, emotional, and financial benefits of having one's father legally identified are irrefutable. They suggest that paternity should be established, regardless of the ability of the father to pay child support. They argue that the role of both parents is critical in building the self-esteem of their children and helping the children become self-sufficient members of the community. Current literature and studies suggest that in most cases visitation with the noncustodial parent is important to the healthy emotional development of children. It is now widely accepted that positive, engaged fathering together with child support are associated with lower levels of behavioral problems and improved academic achievement among children. Children with regular contact with their noncustodial parent often adjust better than those denied such contact. Moreover, generally it is in the best interest of the child to receive the social, psychological, and financial benefits of a relationship with both parents. Visitation (i.e., contact with one's children) is the primary means by which noncustodial parents carry out their parenting duty. The language regarding births to unmarried women has changed in significant ways. What once were referred to as "bastard" or "illegitimate" children are now termed "out-of-wedlock," "outside of marriage," or "nonmarital" births. The stigma and shame that was once attached to these children is generally no longer recognized by the public. Some commentators in fact claim that our nation has gone too far and that now the media, in particular, tends to glorify unwed mothers, especially if they are famous. Others contend that it is often the case that adults pursue individual happiness in their private relationships, which may be in direct conflict with the needs of children for stability, security, and permanence in their family lives. It also is recognized that most people, especially unmarried parents, have a positive attitude towards marriage. Most unmarried parents value marriage but may be reluctant to marry because of real or perceived barriers. Based on information from the Fragile Families and Child Wellbeing study, at the time of their child's birth 72% of unmarried mothers said that their chances of getting married were 50/50 or better and 65% said that marriage is better for children (the comparable percentages for unmarried fathers were 90% and 78%). Some researchers maintain that many couples, to a certain extent, put marriage on a pedestal and are thus reluctant to marry until everything is perfect (e.g., they have a middle-class income, can afford a nice wedding, can afford a house). Some observers contend that the problem is not the weakening of marriage (about 80% of all women ages 15 and older eventually marry), but rather the de-linking of marriage and having children and the abdication of the traditional view of marriage as a life-long commitment. Some researchers and policymakers argue that although couple relationships are a private matter, an overwhelming body of evidence suggests that not all family structures produce equal outcomes for children. They maintain that there is widespread agreement that a healthy, stable (i.e., low-conflict) family with two biological parents is the best environment for children. Finally, some observers assert that we as a society have not strayed too far, and that it is not too late to return to the somewhat old-fashioned, but not simplistic, precept of falling in love, getting married, and having a baby, in that order. An examination of nonmarital births from a demographic perspective is perhaps the only analysis that does not view nonmarital births as a negative phenomenon. 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. The replacement rate is the rate at which a given generation can exactly replace itself. The fertility level required for natural replacement of the U.S. population is about 2.1 births per woman (i.e., 2,100 births per 1,000 women). The nation's total fertility rate—the number of children the average woman would be expected to bear in her lifetime—generally has been below the replacement level since 1972. In 2006 and 2007, the U.S. total fertility rate reached the replacement rate. However, the total fertility rate has steadily declined over the last six years. The total fertility rate for the United States was 1,869.5 births per 1,000 women in 2013. Given that the marital birth rate has been decreasing over time, if the birth rate of unmarried women significantly decreased, the U.S. population would cease growing (if immigration is excluded). This means that those who support policies to lower nonmarital fertility do so at the risk of lowering overall U.S. fertility that has been hovering near replacement levels. Although marriage and family life are generally considered private issues, they have become part of the public arena primarily because of public policies that help families affected by negative outcomes associated with nonmarital births to maintain a minimum level of economic sufficiency. The abundance of research on the subject of the impact on children of various living environments also raises the stakes, in that it is now almost unanimously agreed that children living with married biological parents fare better on a host of measures—economic, social, psychological, and emotional—than children living with a single parent or in a step-parent or cohabiting situation. Some observers contend that although women of all age groups are having children outside of marriage, given the scarcity of resources in most areas of public finance, it may be wiser to pursue a strategy that focuses primarily on reducing nonmarital births of adolescents and women in their early twenties. One of the trends that this report highlights is that although there has been a rise in nonmarital births, it does not mean that there has been a subsequent rise in mother-only families. Instead, it reflects the rise in the number of couples who are in cohabiting relationships. Because the number of women living in a cohabiting situation has increased substantially over the last several decades, many children start off in households in which both of their biological parents reside. Nonetheless, cohabiting family situations are disrupted or dissolved much more frequently than married-couple families. Given the patterns of swift transitions into and out of marriage and the high rate of single parenthood, a family policy that relies too heavily on marriage will not help the many children who will live in single-parent and cohabiting families—many of them poor—during most of their formative years. Moreover, national data from the 2002 panel of the National Survey of Family Growth indicate that 14% of white men, 32% of black men, and 15% of Hispanic men had children with more than one woman. Thus, children in the same family may potentially face different outcomes. For example, children with the same mother and different fathers may potentially face less desirable outcomes if their mother marries the biological father of their half-brothers or half-sisters. The large number of nonmarital births has added to the complexity of families. Children now live in a myriad of living situations. Some may live with both biological parents who may or may not be married, some live with a mom and her cohabiting partner or a dad and his cohabiting partner, others live with a mom and another adult who may or may not be related to the child, or a dad and another adult who may or may not be related to the child. Others live with their mothers only or with their fathers only. Moreover, in each of the family living arrangements mentioned there may or may not be other children, some full siblings, some half-siblings, some step-siblings or perhaps unrelated. Nonmarital childbearing, cohabitation, divorce, re-partnering, and multi-partner fertility (i.e., adults who have biological children by more than one partner) significantly impact children, and public policies that may work for less complicated families may not work for them. 

Summary: Although nonmarital births (i.e., births to unmarried women) are not a new phenomenon, their impact on families has not diminished and there is much agreement that the complexity of modern family relationships and living arrangements may further complicate the well-being of children born to unwed mothers. For the past six years (2008-2013), the percentage of all U.S. births that were nonmarital births remained unchanged at about 41% (1.6 million births per year), compared with 28% of all births in 1990 and about 11% of all births in 1970. Many of these children grow up in mother-only families. Although most children who grow up in mother-only families or step-parent families become well-adjusted, productive adults, the bulk of empirical 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. In the United States, nonmarital births are widespread, touching families of varying income class, race, ethnicity, and geographic area. Many analysts attribute this to changed attitudes over the past few decades 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. With respect to men, it appears that one result of the so-called sexual revolution is that many men now believe that women can and should control their fertility via contraception or abortion and have become less willing to marry the women they impregnate. Factors that are associated with the historically high levels of nonmarital childbearing include an increase in the median age of first marriage (i.e., marriage postponement), decreased childbearing of married couples, increased marital dissolution, an increase in the number of cohabiting couples, increased sexual activity outside of marriage, participation in risky behaviors that often lead to sex, improper use of contraceptive methods, and lack of marriageable partners. The data indicate that for all age groups, a growing share of women are having nonmarital births. Women ages 20 through 24 currently have the largest share of nonmarital births. Although there has been a rise in nonmarital births, it does not mean that there has been a subsequent rise in mother-only families. Instead, it reflects the rise in the number of couples who are in cohabiting relationships; in fact, recent data indicate that more than half of nonmarital births are to cohabiting parents. Because the number of women living in a cohabiting situation has increased substantially over the last several decades, many children start off in households in which both of their biological parents reside. Nonetheless, cohabiting family situations are disrupted or dissolved much more frequently than married-couple families. Moreover, the family complexity that sometime starts with a nonmarital birth may require different public policy strategies than those used in the past for mother-only families. This report analyzes the trends in nonmarital childbearing, discusses some of the characteristics of unwed mothers, addresses some issues involving the fathers of children born outside of marriage, and offers some concluding remarks.