According to "Why Marriage Matters, Thirty Conclusions from the Social Sciences," a report from the Institute for American Values and the National Marriage Project, in the latter half of the 20th century, divorce posed the biggest threat to marriage in the United States.

"No more," says the report. "Today, the rise of cohabiting households with children is the largest unrecognized threat to the quality and stability of children's family lives."

The study analyzes the impact of cohabitation on the family and specifically children based on recent scholarship.

The report is broken down into 30 conclusions, which make up the bulk of this list. These conclusions can be subscribed to five fundamental themes.

1. Children are less likely to thrive in cohabiting households, compared to intact, married families.

2. Family instability is generally bad for children.

3. American family life is becoming increasingly unstable for children.

4. The growing instability of American family life also means that contemporary adults and children are more likely to live in what scholars call "complex households."

5. The nation's retreat from marriage has hit poor and working-class communities with particular force.

The full report can be downloaded as a PDF or purchased as a booklet from The Institute for American Values website.

Related article: Family structure counts

Marriage increases the likelihood that fathers and mothers have good relationships with their children

Mothers as well as fathers are affected by the absence of marriage. Single mothers on average report more conflict with and less monitoring of their children than do married mothers. As adults, children from intact marriages report being closer to their mothers on average than do children of divorce.

Children's relationships with their father depend even more on marriage than do children's relationships with their mother. Sixty-five percent of young adults whose parents divorced had poor relationships with their fathers (compared to 29 percent of non-divorced families). On average, children whose parents divorce or never marry see their fathers less frequently and have less affectionate relationships with their fathers than do children whose parents got and stayed married.

Children are most likely to enjoy family stability when they are born into a married family

There is an emerging scholarly consensus that family stability in and of itself is linked to positive child outcomes. By contrast, children who are exposed to family transitions — from a divorce to the breakup of a mother's romantic relationship with a live-in boyfriend — are more likely to experience behavioral problems, drug use, problems in school, early sex and loneliness.

Only 13 percent of children born to married parents experience a maternal partnership transition by age 3 compared to 50 percent of cohabiting parents.

Family transitions are thought to harm a mother's ability to interact positively with her child(ren) by affecting her economic, social and psychological resources. They also necessitate the establishment of new routines and relationships that may be difficult for children to navigate.

Children are less likely to thrive in complex households

Over the last four decades, increases in divorce, cohabitation and nonmartial childbearing have increased the prevalence of complex households — where children share a household with stepsiblings, half-siblings, stepparents, or with adults with whom they are unrelated by marriage, adoption or blood.

Children are more likely to suffer economically, psychologically and socially when they live in complex households, in part because such households often do not have clear norms, boundaries and a clear family identity to prove stability, direction and purpose to their members and to the relationships within those households.

Cohabitation is not the functional equivalent of marriage

As a group, cohabitors in the United States more closely resemble singles than married people, though cohabitation is an exceptionally heterogeneous status, with some partners treating it as a prelude to marriage, others as an alternative to marriage, others as an opportunity to test for marriage, and still others as a convenient dating relationship.

Children with cohabiting parents have outcomes more similar to the children living with single (or remarried) parents than children from intact marriages. In other words, children living in cohabiting unions do not fare as well as children living in intact, married families.

Cohabitation differs from marriage in part because Americans who choose solely to live together are less committed to each other as partners and their future together. Partly as consequence, cohabiting couples are less likely than married couples to pool their income. Another challenge confronting cohabiting couples is that partners often disagree about the nature and future of their relationship.

Growing up outside an intact marriage increases the likelihood that children will themselves divorce or become unwed parents

Children whose parents divorce or fail to marry are more likely to become young unwed parents, to enter their marriages with lower commitment, to experience divorce themselves someday, to marry as teenagers, and to have unhappy marriages and/or relationships. Daughters raised outside of intact marriages are approximately three times more likely to end up young, unwed mothers than are children whose parents married and stayed married.

Parental divorce increases the odds that adult children will also divorce by at least 50 percent, partly because children of divorce are more likely to marry prematurely and partly because children of divorce often marry other children of divorce, thereby making their marriage even more precarious.

Marriage is a virtually universal human institution

Marriage exists in virtually every known human society. The shape of marriage varies considerably in different cultural contexts, but at least since the beginning of recorded history — in all the flourishing varieties of human cultures documented by anthropologists — marriage has been a universal human institution. As a virtually universal human idea, marriage involves regulation the reproduction of children, families and society.

Marriage, and a normative commitment to marriage, foster high-quality relationships between adults, as well as between parents and children

By offering legal and normative support and direction to a relationship, by providing an expectation of sexual fidelity and lifelong commitment, and by furnishing adults a unique social status as spouses, marriage typically fosters better romantic and parental relationships that alternatives to marriage.

For all these reasons, in part, adults who are married enjoy happier, healthier and less violent relationships compared to adults who are in dating or cohabiting relationships.

Marriage has important biosocial consequences for adults and children

Marriage has biological consequences for adults and children. We are just beginning to discover the myriad ways that marriage seems to promote good outcomes in what social scientists call the "biosocial" area of life — the connection between our social relationships and how our bodies function. In the past decade, two marriage-related biosocial outcomes have emerged as particularly important.

First, marriage appears to reduce men's testosterone levels. For this outcome, however, cohabiting men appear to be affected just as much as are married men.

Secondly, girls appear to benefit in their sexual development from growing up in an intact, married family. Extensive research by psychologist Bruce Ellis and others indicates that adolescent girls who grow up apart from an intact, married household are significantly more likely to have early menstruation, premature sexual activity, and a teenage pregnancy.

Divorce and unmarried childbearing increase poverty for both children and mothers, and cohabitation is less likely to alleviate poverty than is marriage

Research has consistently show that both divorce and unmarried childbearing increase the economic vulnerability of both children and mothers. Changes in family structure are an important cause of new entries into poverty (although a decline in the earnings of the household head is the single most important cause). Child poverty rates are high in part because of the growth of single-parent families. In fact, some studies indicate that all of the increase in child poverty since the 1970s can be attributed to increases in single parenthood due to divorce and nonmarital childbearing.

Bottom line: Cohabitation does not alleviate poverty as well as marriage does. The ratio of income to needs for children in cohabiting families is .43 points lower than that of those in married families.

Married couples seem to build more wealth on average than singles or cohabiting couples

Marriage seems to be a wealth-creating institution. Married couples build more wealth on average than do otherwise similar singles or cohabiting couples, even after controlling for income.

Marriage partners appear to build more wealth for some of the same reasons that partnerships in general are economically efficient. Martial social norms that encourage heath, productive behavior and wealth accumulation (such as buying a home) also appear to play a role.

Marriage reduces poverty and material hardship for disadvantaged women and their children

Focusing on low-income families econimoist Robert I. Lerman found that married couples with children generally had lower levels of material hardship — that is, they were less likely to miss a meal or fail to pay their utilities, rent or mortgage — compared to other families, especially single-mothers living alone.

In another study, he found that mothers with low academic abilities who married saw their living standards end up about 65 percent higher than similar single mothers living with no other adult, more than 50 percent higher than single mothers living with another adult, and 20 percent higher than mothers who were cohabiting.

Minorities benefit economically from marriage also

The economic benefits associated with marriage are not limited to whites. Research also suggests that African-Americans and Latinos benefit materially from marriage. Studies find marriage effects at the community and
individual levels.

At the individual levels, one study found that black single mothers who marry see their income rise by 81 percent (compared to an income increase of 45 percent for white single mothers). This same study found that the income of black children fell by 53 percent two years after a divorce.

Married men earn more money than do single men with similar education and job histories

A large body of research, both in the United Stares and other developed countries, finds that married men earn between 10 and 40 percent more than do single men with similar education and job histories. While selection effects may account for part of the marriage premium (insofar as men with more stable and better-paying jobs are more likely to marry), the most sophisticated, recent research appears to confirm that marriage itself increases the earning power of men on the order of 21 to 24 percent.

Parental divorce (or failure to marry) appears to increase children's risk of school failure

Parental divorce or nonmarriage has a significant, long-term negative impact on children's educational attainment. Children of divorced or unwed parents have lower grades and other measures of academic achievement, are more likely to be held back, and are more likely to drop out of high school.

Parental divorce reduces the likelihood that children will graduate from college and achieve high-status jobs

Parental divorce appears to have long-term consequences on children's socioeconomic attainment. While most children of divorce do not drop out of high school or become unemployed, as adults, children or divorced parents have lower occupational status and earnings and have increased rates of unemployment and economic hardship. They're less likely to attend and graduation from college and also less likely to attend and graduate from four-year and highly selective colleges, even after controlling for family background and academic and extracurricular achievements.

Children who live with their own two married parents enjoy better physical health, on average, than do children in other family forms

Longitudinal research suggests that parental divorce and cohabitation increase the incidence of health problems in children. For example, in one recent longitudinal study the probability that a 5-year-old child with stably-married parents was in excellent health was .69, compared to probabilities of .65 for parents who divorced, .62 for those whose parents stably cohabited and .59 for those who parents dissolved their cohabitation.

Parental marriage is associated with a sharply lowered risk of infant mortality

Babies born to married parents have lower rates of infant mortality. On average, having an unmarried mother is associated with approximately 50 percent increase in the risk of infant mortality. While parental marital status predicts infant mortality in both blacks and whites, the increased risk due to the mother's martial status is greatest among the most advantaged: white mothers over the age of 20.

Marriage is associated with reduced rates of alcohol and substance abuse for both adults and teens

Married men and women have lower rates of alcohol consumption and abuse than do singles (including cohabitors). Longitudinal research confirms that young adults, particularly men, who marry tend to reduce their rates of alcohol consumption and illegal drug use.

Children whose parents marry and stay married also have lower rates of substance abuse, even after controlling for family background and the genetic traits of the parents. Twice was many young teens in single-mother families and stepfamilies have tried marijuana (and young teens living with single fathers were three times as likely).

Married people, especially married men, have longer life expectancies than do otherwise similar singles

Married people live longer than do otherwise similar people who are single or divorced. Husband as well as wives live longer on average, even after controlling for race, income and family background.

In most developed countries, middle-aged single, divorced or widowed men are about twice as likely to die as married men, and non married women face risks about one-and-a-half times as great as those faced by married women.

Marriage is associated with better health and lower rates of injury, illness and disability for both men and women

Both married men and women enjoy better health on average than do single, cohabiting or divorced individuals. Selection effects regarding divorce or remarriage may account for part of this differential. Although research has found no consistent pattern of such selection. Married people have higher incomes and wealth, and adopt healthier lifestyles than do otherwise similar singles.

Marriage seems to be associated with better health among minorities and the poor

A recent report from the Centers for Disease Control indicates that African-American, Latino and low-income adults also enjoy health benefits from marriage. African-American, Latino and poor adults who are married are less likely to be in poor health, to have activity limitations, to smoke, to have a drinking problem and to suffer serious psychological distress, compared to cohabiting, never-married, divorced,and widowed adults who were African-American or Latino.

Children whose parents divorce have higher rates of psychological distress and mental illness

In the last four decades, a large body of research on divorce has accumulated that generally indicates that divorce often causes children considerable emotional distress and doubles the risk that they will experience serious psychological problems later in life. Children of divorce are at higher risk for depression and other mental illness over the course of their lives, in part because of reduced educational attainment, increased risk of divorce, marital problems and economic hardship.

Cohabitation is associated with higher levels of psychological problems among children

Studies find that children in cohabiting families are significantly more likely to experience depression, difficulty sleeping, feelings of worthlessness, nervousness and tension, compared to children in intact, married households.

For example, one nationally-representative study of 6-to 11-year-olds found that 15.7 percent of children in cohabiting families experienced serious emotional problems (e.g., depression, feelings of inferiority, etc.), compared to just 3.5 percent of children in families headed by married biological or adoptive parents.

Family breakdown appears to increase significantly the risk of suicide

High rates of family fragmentation are associated with an increased risk of suicide among both adults and adolescents. Divorced men and women are more than twice as likely as their married counterparts to attempt suicide. Married individuals were also substantially less likely to commit suicide than were divorced, widowed or never-married individuals.

In the last half-century, suicide rates among teens and young adults have tripled. The single "most important explanatory variable," according to one new study, "is the increased share of youths living in homes with a divorced parent."

Married mothers have lower rates of depression than do single or cohabiting mothers

The absence of marriage is a serious risk factor for maternal depression. Married mothers have lower rates of depression than do cohabiting or single mothers. Cohabiting mothers are more likely to be depressed because they are much less confident that their relationship will last, compared to married mothers. Single mothers are more likely to be depressed by the burdens associated with parenting alone.

Boys raised in non-intact families are more likely to engage in delinquent and criminal behavior

Even after controlling for factors such as race, mother's education, neighborhood quality and cognitive ability, one recent study found that boys raised in single-parent homes are about twice as likely (and boys raised in stepfamilies are more than two-and-half times as likely) to have committed a crime that leads to incarceration by the time they reach their early thirties.

Marriage appears to reduce the risk that adults will be either perpetrators or victims of crime

Overall, single and divorced women are four to five times more likely to be victims of violent crime in any given year than are married women. Single and divorced women are almost 10 times more likely than are wives to be raped and about three times more likely to be victims of aggravated assault.

For instance, the U.S. Department of Justice estimates that the violent victimization rate was 17 per 1,000 married women compared to more than 60 to 1,000 single or divorced women in 1992-1993. Similarly, compared to husbands, unmarried men are about four times as likely to become victims of violent crime.

Married women appear to have a lower risk of experiencing domestic violence than do cohabiting or dating women

While young women must recognize that marriage is not a good strategy for reforming violent men, a large body of research shows that being unmarried, and especially living with a man outside of marriage, is associated with an increased risk of domestic abuse. One analysis of the National Survey of Families and Households found that cohabitors were more than three times more likely than spouses to say that arguments became physical during the last year (13 percent of cohabitors verses 4 percent of spouses).

A child who is not living with his or her own two married parents is at greater risk of child abuse

Children living with single mothers, mother's boyfriends or stepfathers are more likely to become victims of abuse. Children living in single-mother homes have increased rates of death from intentional injuries.

Another national study found that 7 percent of children who have lived with one parent had experienced sexual abuse compared to 4 percent of children who lived with both biological parents, largely because they had more contact with unrelated adult males.

Other research found that, although boyfriends contribute less than 2 percent of nonparental childcare, they commit half of all reported child abuse by nonparents.

There is a growing marriage gap between college-educated Americans and less-educated Americans

As late as the 1970s, the vast majority of adult Americans were living in an intact marriage, and almost nine in 10 children were born into married families. No longer. Now, less than half of adults are married. This retreat from marriage has hit the poor, working-class and minority communities with particular force. By contrast, marriage trends among more educated and affluent Americans have largely stabilized or taken a turn for the better.

For instance, nonmarital childbearing rose more than six-fold from 5 percent in 1982 to 34 percent in 2006-2008 among white high-school educated Americans.

Over this same period, family instability rose among Americans who did not have college degrees, but fell among the college-educated Americans.


According to the study, "marriage is more than a private emotional relationship. It is also a social good. This is not a claim that everyone can or should marry, or that every child raised outside of marriage is damaged as a result. Marriage is not a panacea that will solve all of our social problems. But marriage matters."

The report offers three specific fundamental conclusions:

1. The intact, biological, married family remains the gold standard for family life in the United States.

2. Marriage is an important public good.

3. The benefits of marriage extend to poor, working-class and minority communities.