The extent to which abused children become abusive parents is controversial. A large multigenerational study reported in the March 27 issue of Science provides a perspective on this issue.

Social scientists gathered data from metropolitan St. Louis, following childhood victims of physical or sexual abuse or neglect over 30 years to determine if they had become abusive parents. Data were gathered from court records, documents from the U.S. Child Protective Services, and extensive personal interviews conducted over a number of years. Results were compared to a control group of children who had not suffered abuse or neglect. The control group was drawn from similar neighborhoods and were matched to the study group by race, sex, age, and family, economic background.

Surprisingly, parents who had experienced physical abuse in childhood were no more likely to abuse their offspring than parents in a control group. There was a measurable incidence of abuse in both control and study groups.

Parents who had been sexually abused or neglected in childhood, however, were more than twice as likely to mistreat their children when compared to members of the control group. The study’s authors point out that a number of subjects of abuse were lost to follow-up. Families in the study were possibly followed more closely by Child Protective Services since they had a history of abuse, and this may have led to a reporting bias in the study.

The study suggests that sexual abuse and neglect may lead to more lasting emotional trauma in children which, in turn, increases the possibility of these children growing into abusive adults.

A 2014 report in Nature Neuroscience offers a possible explanation for the extension of child abuse across generations. Very young mice were exposed to non-physical stress such as irregular contact with their mothers or unpredictable feeding times. Their mothers were also exposed to unpredictable stress. These events altered the chemical composition or environment within male reproductive cells. These changes persisted through sequential litters of mice. The structure of DNA, where our genetic code rests, was not changed.

The altered chemicals — called sncRNAs, and common in sperm cells in all mammalian species — were associated with behavioral changes in the mice, which became more aggressive and an accelerated metabolism. The changes in behavior and metabolism persisted across generations.

When altered sncRNAs were injected into fertilized eggs, the subsequent offspring exhibited similar changes in behavior and metabolism.

The study makes a strong case that emotional trauma of very young animals leads to lasting changes in male reproductive cells and in behavior linked to these changes. Similar research will be needed in other mammals to validate observations in mice. The current study raises important questions about the effects of stress on very young children.

Abused children are not uniformly destined for violent adulthood. Assuming abuse comes to the attention of social services, abused children can, if necessary, be removed from their environment. They can ideally receive sustained counseling and follow-up. Hopefully, other significant adults such as teachers, coaches and religious leaders can have a healing impact upon their lives.

While social and scientific research clarifies the causes and effects of child abuse, the immediate challenge for politicians and citizens is to assure that child abuse is progressively diminished in our society. This requires robust efforts to educate parents in the proper care of children, to provide comprehensive counseling and support to victims when abuse is identified and to raise awareness for all us to report abuse when we suspect it.