UNC study: Parenting can override effect of genes in how babies respond...( CHAPEL HILL Everyone gets stressed ...),Health

CHAPEL HILL Everyone gets stressed, even babies.

Now, it appears how infants respond to stress is linked to if they have a particular form of a certain gene, according to a new study from the University of North Carolina at Chapel Hill.

Just as significantly, researchers say they have also found that good parenting as early as within the first year of a child's life can counter the effect the gene has in babies who initially do not respond well to stressful situations.

"Infancy is an important time for developing behavioral and biological processes," said the study's lead author, Cathi Propper, Ph.D., research scientist at UNC's Center for Developmental Science. "Although these processes will continue to change over time, parenting can have important positive effects even when children have inherited a genetic vulnerability to problematic behaviors."

The study findings appear in the September/October 2008 issue of the journal Child Development.

Researchers looked at 142 infants over the first year of their lives, when the children were 3, 6 and 12 months old. On each occasion, they were placed in a stressful situation being separated from their mothers and researchers measured the infants' heart rates, looking specifically at a type of cardiac response called vagal tone. Vagal tone acts like a brake on the heart when the body is in a calm state, but during challenging situations, the brake is withdrawn and the level of vagal tone goes down, allowing heart rate to increase so the body can actively deal with the challenge.

Researchers also collected DNA from the infants to see which form of a dopamine receptor gene they carried. Previous studies have shown that adolescents and adults with specific forms of this gene are more likely to have problems such as aggression, substance abuse and other risky behaviors.

When the babies were 6 months old, researchers also videotaped the mothers
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