Journal Issue: Fragile Families Volume 20 Number 2 Fall 2010
For much of the nation's history, the vast majority of American children were born into and spent their childhood in intact married-couple families. Almost the only exceptions were children whose families suffered a parental death. Over the course of the twentieth century, however, as divorce became more common, an increasing share of children experienced a breakup in their families of origin and went on to spend at least some portion of their childhood or adolescence living with just one parent or with a parent and stepparent. A large research literature developed examining the effects of such living situations on child outcomes.
More recently, as unwed births have risen as a share of all births, family structure in the United States has increasingly featured "fragile families" in which the mother is unmarried at the time of the birth. Children born into fragile families spend at least the first portion of their lives living with a single mother or with a mother who is residing with a partner to whom she is not married. For simplicity, we will refer to the first of these types of fragile family as single-mother families and the second as cohabiting-couple families.1
An astonishing 40 percent of all children born in the United States in 2007 were born to unwed parents and thus began life in fragile families. That share was more than twice the rate in 1980 (18 percent) and an eightfold increase from the rate in 1960 (5 percent).2 Half of the children born to unwed mothers live, at least initially, with a single mother who is not residing with the child's biological father (although about 60 percent of this group say they are romantically involved with the father), while half live with an unwed mother who is cohabiting with the child's father.3 These estimates imply that today one-fifth of all children are born into single-mother families, while another fifth are born into cohabiting-couple families. Therefore, in examining the effects of unwed parenthood on child outcomes, it is important to consider both children living with single mothers and those living in cohabiting-couple families.
Single parenthood and cohabitation have lost much of their stigma as their prevalence has increased. But there are still many reasons to be concerned about the well-being of children in fragile families, and, indeed, research overwhelmingly concludes that they fare worse than children born into married-couple households.4 What remains unclear is how large the effects of single parenthood and cohabitation are in early childhood and what specific aspects of life in fragile families explain those effects.
In this article, we review what researchers know about the effects of fragile families on early child development and health outcomes, as well as what they know about the reasons for those effects. Many underlying pathways or mechanisms might help explain the links between fragile families and children's cognitive, behavioral, and health outcomes. Identifying these mechanisms is important to efforts by social scientists to understand how family structure affects child outcomes and to develop policies to remedy negative effects. A challenge that must be addressed is the role of "selection." The characteristics of young women and men who enter into single parenthood or cohabiting relationships differ from those of men and women in married-couple families, and those pre-existing characteristics might lead to poorer outcomes for children regardless of family structure. Parents in fragile families, for example, tend to be younger and less educated than those in married-couple families, and they may also differ in ways that cannot readily be observed even using detailed survey data. A final question is the degree to which the stability of the family setting affects how well children fare. In fact, recent research holds that it is in large part the stability of the traditional family structure that gives it its advantage.
We highlight new answers to these questions from studies using data from the Fragile Families and Child Wellbeing Study (FFCWS)—a data set designed specifically to shed new light on the outcomes of children born into single-mother and cohabiting families and how they compare with those of children in married-couple families. The study follows children from birth and collects data on a rich array of child health and developmental outcomes, thus providing evidence on how children's outcomes differ depending on whether they grow up in single and cohabiting versus married-couple families and on the factors that might underlie those differences.
We review the evidence on the effects of fragile families on child well-being by comparing outcomes for three types of families. The first type is families where children live with two married parents (for simplicity, we refer to these as traditional families). In this category are children living with their married biological parents as well as children living with married stepparents. (Research has documented differences in outcomes between these two subgroups of children, but those differences are not our focus here.) Rather, we are interested in two other types of families—both fragile families—that have become increasingly prevalent in recent years. One is single-mother families in which the mother was not married at the time of the birth and in which she is not currently living with a boyfriend or partner. The other is cohabiting-couple families in which the mother was not married at the time of the birth but is currently cohabiting with a boyfriend or partner, who might be either the child's biological parent or a social parent (someone who is not biologically related to the child but who functions at least partially in a parental role). We do not distinguish between families that share and do not share households with extended family members or with other families or friends. We also do not distinguish between single mothers who are in a dating or visiting relationship and those who are not. Such distinctions likely matter, but our focus is on the three more general family types: traditional married-couple family, single-mother family, and cohabiting-couple family.