Stressed moms, genes may cause shy kids
By ANTHONY ROTUNNO 
WASHINGTON, March 5 (UPI) -- Shyness in children might in part stem from a certain stress-related gene that's activated by living with stressed mothers, according to a new study. 
Children can have either the "long" or "short" variation of a gene responsible for regulating the amount of serotonin, or a chemical that transmits information in the brain. Kids who have the short variation, and whose parents experience continuously high stress levels, are more likely to become shy as they grow older, according to University of Maryland researchers.
Kids with the short variation who also had stressed mothers were more likely to continue to be shy as they got older than kids who had the same genetic structure and moms who reported they weren't stressed, said Nathan Fox, an author of the study and professor of human development at the University of Maryland's College Park campus. The study was published in the February issue of Current Directions in Psychological Science. 
Children with the long variation of the gene, and whose mothers reported having high stress levels, did not show tendencies towards shyness, Fox said. This suggests the combination of having both a short variation of the gene and stressed parents leads to reserved kids.
Shyness in young children can have disadvantages, including a higher likelihood of anxiety and a smaller circle of friends, according to C. Robert Cloninger, professor of psychiatry, genetics and psychology at Washington University in St. Louis. 
"Being shy makes it harder to deal with strangers, but also keeps you from being reckless," he said.
The study examined the behavior of 150 randomly selected children and included data collected on each child between the ages of 4 months and 7 years, Fox said. The stress levels reported by each child's mother were examined in conjunction with each child's DNA, he said, and the researchers monitored whether or not a tendency towards shyness developed.
To determine whether or not children developed shyness, each child was observed while playing with a group of kids he or she did not know. The study's conclusions were based on the researchers' behavioral analyses of the children and on the results of a questionnaire filled out by each child's mother at the end of the evaluation period, he said.
"It doesn't matter if you use our behavioral analysis or the mother's questionnaire to determine the child's shyness," Fox said. "Both methods were on point with each other."
This study is not conclusive; the authors said similar studies need to be conducted to confirm their results. 
Fox's study supports a small and growing amount of literature emphasizing that the combination of genetics and environment is critical in determining personality and future development of children, Cloninger said.
"It is a reasonable model of how parental care and social supports interact with whether or not the child is already inhibited (genetically)," he said. "It is very much in line with other results that have been found." 
Highly stressed parents tend to be more overprotective of their children, Fox said, which can heighten their child's anxiety level and lead to shyness. Since this connection has been confirmed, he said, researchers need to identify how parents' behavior stimulates the gene and how it acts with serotonin to create a shy kid. 
Parents should be well aware of their child's temperament and try to modify their behavior according to the personalities of their children. Those parents who find themselves under constant stress should try to practice a more relaxed style of parenting to avoid having an overly shy child, he said. 
"This overintrusive, alarmist kind of parenting is not a good thing," Fox said. "The quality of the parenting is going to be critical in terms of whether or not the kid continues to be shy."