One of the most embarrassing of childhood conditions - bedwetting - is probably caused by genetic factors beyond a child’s control, researchers say.

Doctors have known for years that bedwetting can run in families. But a Danish research team has, for the first time, linked the trait to a specific set of genes located on the 13th chromosome.

The new findings “will legitimize something that has been subject to myth,” said Dr. Donald Shifrin, an associate professor of pediatrics at the University of Washington. “We can now say to parents, ‘Look, this is not your fault’ … What the medical profession will get out of this may be less than what the parenting profession will get out of this.”

Ten percent of 8-year-olds, Shifrin said, are affected by what doctors call primary noctural enuresis - they have never experienced an extended period of dryness. Bedwetting disappears gradually as children age.

By adolescence, it affects only about 1 percent of children, Shifrin said.

Bedwetting often is seen as a behavioral problem, stemming from social or emotional difficulties. Some parents blame themselves; others resort to punishing their children.

But Shifrin said doctors have found that if one parent was a bedwetter, there is a 30 percent to 40 percent chance a child will be. If both parents were, the probability rises to 60 percent to 70 percent.