No one doubts that genes affect personality as well as ability, that peers are vital, and that schools and cultures influence what, and how much, children learn. Some experts have gone further, suggesting that genes, peers, and communities are so influential that parenting has little impact—unless it is grossly abusive (Harris, 1998, 2002; McLeod et al., 2007). This suggestion arose from studies about the impact of the environment on child development.

Many studies find that children are much less affected by shared environment (influences that arise from being in the same environment, such as two siblings living in one home, raised by their parents) than by nonshared environment (e.g., the experiences in the school or neighborhood that differ between one child and another).

Almost all personality traits and intellectual characteristics can be traced to the combined influence of genes and nonshared environments, with little left over for the shared influence of being raised together. Even psychopathology, happiness, and sexual orientation (Burt, 2009; Långström et al., 2010; Bartels et al., 2013) arise primarily from genes and nonshared environment.

Since research finds that shared environment has little impact, could it be that parents are merely caretakers? Mothers and fathers need to provide basics (food, shelter) and are harmful when abusive, but might their household restrictions, routines, and responses be irrelevant? If a child becomes a murderer or a hero, could that be genetic and nonshared? Perhaps parents deserve neither blame nor credit!

Recent findings, however, reassert parent power. The analysis of shared and nonshared influences was correct, but the conclusion was based on a false assumption. Siblings raised together do not share the same environment.

For example, if relocation, divorce, unemployment, or a new job occurs in a family, the impact on each child depends on his or her age, genes, and gender. Moving to another town upsets a school-age child more than an infant, divorce harms boys more than girls, poverty may hurt preschoolers the most, and so on.

The variations above do not apply for all siblings: Differential susceptibility means that one child is more affected, for better or worse, than another (Pluess & Belsky, 2010). When siblings are raised together, all experiencing the same dysfunctional family, then their genes, age, and gender may lead one child to become antisocial, another to be pathologically anxious, and a third to be resilient, capable, and strong (Beauchaine et al., 2009).

Further, parents do not treat each of their children the same, in part because birth order and gender differ. It is mistaken to assume that family experiences are the same for the eldest and the youngest. Even identical twins might have different family experiences, as in the following.

Family structure refers to the legal and genetic connections among related people. Legal connections are via marriage, years of cohabitation, or adoption. Genetic connections are from parent to child, or between siblings, cousins, grandparents and grandchildren, and so on.

Family function refers to how the people in a family work together to care for the family members. Some families function well, others are dysfunctional.

Function is more important than structure, although harder to measure. Some family functions are needed by everyone at every age, such as love and encouragement. Beyond that, what people need from their families differs depending on how old they are: Infants need responsive caregiving, teenagers need guidance, young adults need freedom, the aged need respect.

THE NEEDS OF CHILDREN IN MIDDLE CHILDHOOD What do children need from their families during middle childhood? Ideally, five things:

The final item on the list above is especially crucial in middle childhood: Children cherish safety and stability; they do not like change (Turner et al., 2012). Ironically, many parents move from one neighborhood or school to another during these years. Children who move frequently may be harmed, academically and psychologically (Cutuli et al., 2013).

The problems arising from instability are evident for U.S. children in military families. Enlisted parents tend to have higher incomes, better health care, and more education than do civilians from the same backgrounds. But they have one major disadvantage: They move. In reviewing earlier research, a scientist reports “military parents are continually leaving, returning, leaving again . . . School work suffers, more for boys than for girls, . . . reports of depression and behavioral problems go up when a parent is deployed” (Hall, 2008, p. 52).

About half the military personnel who are on active duty have children, and many of their children learn to cope with the stresses they experience (Russo & Fallon, 2014). To help them, the U.S. military has instituted special programs. Caregivers are encouraged to avoid changes in the child’s life: no new homes, new rules, or new schools (Lester et al., 2011).

DIVERSE STRUCTURES Family diversity should be acknowledged but not exaggerated. More than two-thirds of all U.S. school-age children live with two married adults (see Table 8.2), most often their biological parents. Nuclear families are composed of children and their biological parents (married or not) without other relatives in the same home. Other two-parent structures include adoptive, foster, step, same-sex, and grandparents.

Single-parent families occur when only one parent is present. The United States has many single-parent families: About 31 percent of all U.S. 6- to 11-year-olds live with a single parent.

Rates of various structures change depending on the age of the child: More than half of all contemporary U.S. children will live in a single-parent family for at least a year before they reach age 18. If the children are young, usually the single parent never married; if the children are teenagers, divorce or separation is the most common reason only one parent is at home.

Extended families consist of relatives residing with parents and children. Usually the additional persons are grandparents; sometimes they are uncles, aunts, or cousins of the child.

The crucial distinction between types of families is based on who lives together in the same household, a distinction that does not necessarily reflect the experience of the child. Many so-called single-parent families actually have two parents involved in the child’s life. Likewise, some children see their grandparents every day, even though they do not live with them. The family may function like an extended family, but it is not categorized as such.

In many nations, polygamous families (one husband with two or more wives) are an acceptable family structure. Family function may suffer in that structure, because often income per child is reduced, and education, especially for the girls, is limited (Omariba & Boyle, 2007). On the other hand, many argue that polygamy is preferable to divorce and remarriage, since most fathers who left one wife and married another are less involved with children from their first marriage than they would have been if they were the head of a polygamous family (Calder & Beaman, 2014).

Related to that is the role of stepsiblings, who are part of many family structures. Living in a family with stepsiblings, even for children who are the biological offspring of the current parents, affects family function. Children in these “complex” family structures are less likely to do well in school and in life (Brown et al., 2015).

DIVORCE Scientists try to provide analysis and insight based on empirical data (of course), but the task goes far beyond reporting facts. Regarding divorce, thousands of studies and several opposing opinions need to be considered, analyzed, and combined—no easy task. One scholar who has attempted this analysis is Andrew Cherlin. He has written 13 books and over 200 articles since 1988.

Among the facts that need analysis are these:

Each of these is troubling. Why does this occur? The problem, Cherlin (2009) contends, is that U.S. culture is conflicted: Marriage is idolized, but so is personal freedom. As a result, many people assert their independence by marrying without consulting their parents or community. If such a love-struck couple has a baby, child care becomes overwhelming and family support is lacking. That strains the marriage, precipitating divorce.

However, Cherlin argues, because marriage remains the ideal, divorced adults blame their former mate or their own poor decisions, not the institution or the society. Consequently, they seek another marriage, which may lead to another divorce. (Divorced people are more likely to remarry than single people their age are to marry). Repeated transitions allow personal freedom for the adults but harm the children.

This leads to a related insight. Cherlin suggests that the main reason children are harmed by divorce—as well as by cohabitation, single parenthood, and stepparenthood—is not the legal status of their parents but the lack of stability.

For example, divorces typically include many disruptions: in residence, in school, in family members, and—this may be crucial—in the relationship between child and parent. Divorced parents often become too strict or too lenient, impose premature responsibility or independence, or tell the child things that relieve the adult’s anger or loneliness.

Scholars now describe divorce as a process, with transitions and conflicts before and after the formal event (H. S. Kim, 2011; Putnam, 2011). This process entails repeated changes and ongoing hassles for the children. The child’s ability to cope is particularly compromised if the child is experiencing a developmental transition, such as entering first grade or beginning puberty.

Nonetheless, some researchers believe that divorce may be better for the child than an ongoing, destructive family. As one scientist who studied divorced families for decades wrote:

Although divorce leads to an increase in stressful life events, such as poverty, psychological and health problems in parents, and inept parenting, it also may be associated with escape from conflict, the building of new more harmonious fulfilling relationships, and the opportunity for personal growth and individuation.

[Hetherington, 2006, p. 204]

Not every parent should marry, not every marriage should continue, and not every divorce is harmful. However, every child needs parents to fulfill all five needs of school-age children, and a conflict-filled divorce makes that goal difficult to reach.

As obvious with divorce, the fact that family function is more important for children than family structure does not make structure irrelevant. Structure influences function and vice versa. The crucial question is whether the structure makes it more or less likely that the five family functions mentioned earlier (physical necessities, learning, self-respect, friendship, and harmony/stability) will be fulfilled.

NUCLEAR FAMILIES On average, nuclear families function best; children in the nuclear structure tend to achieve better in school with fewer psychological problems. A scholar who summarized dozens of studies concludes: “Children living with two biological married parents experience better educational, social, cognitive, and behavioral outcomes than do other children” (Brown, 2010, p. 1062).

Do the proven benefits of nuclear families mean that everyone should marry before they have a child, and then stay married? Not necessarily. Some benefits are correlates, not causes.

Education, earning potential, and emotional maturity all correlate with getting married and staying married. For example, if women having their first baby are highly educated, they are usually married (78 percent) at conception; but if they are poorly educated, they are rarely married (only 11 percent) (Gibson-Davis & Rackin, 2014). The development of the child correlates with marital status, but obviously the mother’s education is the main reason, not whether or not she is wed.

Brides and grooms tend to have personal assets before marriage and parenthood, and they bring those assets to their new family. This means that the correlation between child success and married parents occurs partly because of who marries, not because of the wedding. Indeed, for some very low-SES women, marrying a man who is also a high-school dropout with no steady job would actually undercut their ability to give their baby attention. They are better mothers without marrying!

Income correlates with family structure. Usually, married couples live apart from their parents if everyone can afford it. That means that, at least in the United States, an extended family suggests that someone is financially dependent, not that a child has many loving adults at home.

These two factors—mate selection and income—explain some of the correlation between nuclear families and child well-being, but not all of it (Brown, 2010). The fact that the nuclear family is “not as strong as it appears” does not make marriage irrelevant. Ideally, marriage increases mutual affection and support, making both partners wealthier and healthier than either would have been alone. Further, when both parents live with their children day and night, a parental alliance is likely to form. That benefits the child.

Evidence for the benefits of the parental alliance comes from Russia, where recent economic upheaval reduced a man’s average life span from age 64 in 1985 to 59 in 2000. Most at risk for an early death are single men, who have high rates of depression and alcoholism. If a Russian man lives with his wife and children, he tends to take better care of himself and his children (Ashwin & Isupova, 2014).

Shared parenting not only decreases rates of depression, in Russia and elsewhere, but it also decreases child maltreatment. Further, having two parents at home makes it more likely that someone will read to the child, check homework, invite friends over, buy new clothes, and save for college. Of course, having two married parents does not guarantee anything. One of my students wrote:

My mother externalized her feelings with outbursts of rage, lashing out and breaking things, while my father internalized his feelings by withdrawing, being silent and looking the other way. One could say I was being raised by bipolar parents. Growing up, I would describe my mom as the Tasmanian devil and my father as the ostrich, with his head in the sand. . . . My mother disciplined with corporal punishment as well as with psychological control, while my father was permissive. What a pair.

[C., 2013]

This student never experienced a well-functioning parental alliance. Does that help explain why she is now a single parent, having twice married, given birth, and divorced? For everyone, childhood family experiences echo in adulthood. Especially when children are in middle childhood and adolescence, meaningful father–child relationships are difficult for men who do not live with their children, partly because of the children themselves.

One consequence: When children reach “the age of majority” (usually 18) and fathers are no longer legally responsible, many divorced or unmarried fathers stop child support. Unfortunately, most emerging adults need financial support to attend college or live independently, so a long-ago divorce still hinders their development (Goldfarb, 2014).

This benefit for children in nuclear families is more than financial. When remarried adults have incomes comparable to that of nuclear parents, they contribute less, on average, to children who live with them (Turley & Desmond, 2011). Fathers typically spend less time caring for stepchildren than biological children (Kalil et al., 2014b). As adults, stepchildren tend to live farther from either their biological father or their stepfather than other adult children do (Seltzer et al., 2013). Thus, because divorce weakens the parental alliance in childhood, nuclear families tend to be more cohesive lifelong.

OTHER TWO-PARENT FAMILIES We should not exaggerate the benefits of nuclear families. Adoptive and same-sex parents usually function well for children, not only in middle childhood but lifelong. Stepfamilies may also function well if the biological parent has chosen a partner who will be a good parent. Especially when children are under age 2 and the stepparent and the biological parent develop a strong, healthy relationship, the children who live with them may thrive (Ganong et al., 2011).

No structure is guaranteed to function well, but particular circumstances for all three family types—same-sex, adoptive, and step—can nudge in the right direction. The most difficult family function for stepfamilies to fulfill is the fifth one (harmony and stability).

Compared with other two-parent families, stepfamilies more often change residence and community. In addition, family constellations shift: Older stepchildren leave home more often than older biological children, new babies capture parental attention and affection, additional relatives may join the household, and divorce is more common.

Not only is stability more difficult for stepfamilies; harmony is more difficult as well (Martin-Uzzi, & Duval-Tsioles, 2013). Ongoing disputes between the biological parents clash with the child’s loyalty to both parents. A solid parental alliance is elusive when it includes three adults—two of whom had such profound differences that they divorced, plus another adult who is a newcomer to a child they did not raise.

Children who gain a stepparent may be angry or sad, so they often act out (e.g., fight with friends, fail in school, disobey adults). That causes arguments for their newly married parents, who may have opposite strategies for managing misbehavior. Further, disputes between half-siblings in blended families are common. Remember, however, that structure affects function but does not determine it. Many stepparent families are difficult for children, but others function well for everyone (van Eeden-Moorefield & Pasley, 2013).

Finally, the grandparent family is often idealized, but reality is much more complex. If a household has grandparents and parents, the grandparents may be care-receivers more than caregivers. Further, the two adult generations often disagree about discipline, diet, and much else.

Sometimes one or two grandparents provide full-time care with no parents present (called a skipped-generation family, a common form of foster care). The hope is that their experience and maturity will benefit the grandchildren. But that is not necessarily true. Grandchildren who have been removed from their parents often have health or behavioral problems themselves (Hayslip et al., 2014). They are less likely to succeed in school or have supportive, enduring friendships than other children from the same ethnic and economic backgrounds.

SINGLE-PARENT FAMILIES On average, the single-adult structure functions less well for children than the two-parent home does, primarily because the two-adult family usually has more income, time, and stability. Most single parents fill many roles—wage earner, daughter or son, as well as both mother and father—making it hard for any one adult to provide the steady emotional and academic support a child needs.

Rates of single parenthood and single grandparenthood are far higher among African Americans than other ethnic groups. This makes children from single-parent African American families feel less stigmatized, but it does not lighten the burden on the parents. If a single parent is depressed (and many are), that compounds the problem. The following case is an example.

Family structure encourages or undercuts healthy function, but many parents and communities overcome structural problems to support their children. Contrary to the averages, thousands of single-parent families are wonderful. In some European nations, single parents are given many public resources; in other nations, they are shamed and unsupported. Children benefit or suffer accordingly (Abela & Walker, 2014).

Culture is always influential. In contrast to data from the United States, a study in the slums of Mumbai, India, found rates of psychological disorders among school-age children higher in nuclear families than in extended families, presumably because in that culture grandparents, aunts, and uncles provided more care and stability than two parents alone (Patil et al., 2013).

On the other hand, another study found that college students in India who injured themselves (e.g., cutting) were more often from extended families than nuclear ones (Kharsati & Bhola, 2014). One explanation is that these two studies had different populations: College students tend to be from wealthier families, unlike the children in Mumbai.

Although these studies from India differed regarding extended families, both studies found that children from single-parent families had more emotional and academic problems than other children. Of course, some nuclear families are dysfunctional, but in general children are likely to thrive when both biological parents provide direct, daily care.

Two factors impair family function in every structure, ethnic group, and nation: low income and high conflict. Many families experience both: Financial stress increases conflict and vice versa.

WEALTH AND POVERTY Family income correlates with both function and structure. Marriage rates fall in times of recession, and divorce correlates with unemployment. Low SES increases the rate of many problems; “risk factors . . . pile up in the lives of some children, particularly among the most disadvantaged” (Masten, 2014, p. 95).

Several scholars have developed the family-stress model, which holds that any risk factor (such as low income, divorce, single parenthood, or unemployment) damages a family only if it increases stress on the parents, who then become impatient and unresponsive with their children.

If economic hardship is ongoing, if uncertainty about the future is high, if education is low—all these factors increase adult hostility and stress. Thus, as many studies have found, although it is easy to understand why worries about food and housing make adults less patient, their reactions are nonetheless crucial (Valdez et al., 2013; Evans & Kim, 2013; D. Lee et al., 2013).

More income correlates with better family functioning. For example, children in single-mother households do much better if their father reliably pays child support (Huang, 2009). Nations that subsidize single parents (e.g., Austria and Iceland) have smaller achievement gaps between low- and middle-SES children on the TIMSS.

Surprisingly, reaction to wealth may also cause difficulty. Children in high-income families have more than their share of developmental problems. Again, parental reaction may be pivotal. If wealthy parents pressure their children to maintain high achievement, stress can lead the children to drug use, delinquency, and poor academic performance (Luthar & Barkin, 2012).

CONFLICT Every researcher agrees that family conflict harms children, especially when adults fight about child rearing. Such fights are more common in stepfamilies, divorced families, and extended families, but nuclear families are not immune. Children suffer if they witness fights between their parents. Fights between siblings can be harmful, too (Turner et al., 2012).

Some researchers hypothesize that children are emotionally troubled in families with feuding parents because of their genes, not because of what they see. The hypothesis is that the parents’ genes lead to marital problems. If that is true, and if children inherit those same genes, then genes, not experiences, trouble the children whose parents fight.

This hypothesis was tested in a longitudinal study of 867 adult twins (388 monozygotic pairs and 479 dizygotic pairs), all married with an adolescent child. Each adolescent was compared to his or her cousin, the child of one parent’s twin (Schermerhorn et al., 2011). Thus, this study had data from 5,202 individuals—one-third of them adult twins, one-third married to a twin, and one-third adolescents who had half, or a fourth, of the same genes as an adolescent in another family.

The researchers found that, although genes had some influence, witnessing conflict was crucial, causing externalizing problems in boys and internalizing problems in girls. In this study, quiet disagreements did little harm, but open conflict (such as yelling when children could hear) and divorce did (Schermerhorn et al., 2011).