(Center for the Advancement of Health) -- Children who live with highly antisocial fathers show an increase in behavioral problems the longer they live with their father, a new study reports.

Behavioral problems may also increase among children who do not spend time living with their biological father, but only if the father has low levels of antisocial behavior, according to Sara R. Jaffee, Ph.D., of King's College, London, and colleagues.

The study suggests that living with two biological parents may not always be beneficial for children, say the researchers, who urge policymakers to consider the implications of their findings in relation to programs that encourage biological parents to marry.

"Marriage may not be the answer to the problems faced by some children living in single-parent families unless their fathers can become reliable sources of emotional and economic support," Jaffee says.

Jaffee and colleagues analyzed data from 1,116 pairs of 5-year old twins in the United Kingdom, including information on the children's behavior problems, the antisocial behavior of their fathers and the amount of time that the fathers lived with and took care of the twins. Their results are published in the January/February issue of the journal Child Development.

The researchers found that children had more behavior problems, like cheating and swearing, temper tantrums and physical attacks, when they spent less time living with fathers who had low levels of antisocial behavior.

"In contrast, when fathers engaged in high levels of antisocial behavior, the more time they lived with their children, the more conduct problems their children had," Jaffee says, noting that the highly antisocial fathers were less likely to take care of the twins even when they lived with their children.

Jaffee and colleagues' analysis also indicates a possible genetic component to the children's behavioral problems.

"This suggests that fathers who are characterized by high levels of antisocial behavior not only pass on 'risky' genes to their children, but also provide rearing experiences that contribute to the development of their children's antisocial behavior," the researchers say.

This study was supported by the Medical Research Council and the Royal Society-Wolfson Research Merit Award.