Have trouble getting to sleep? Blame your parents. That’s the upshot of a new study of twins that suggests that insomnia is partially hereditary and explained by genetic factors.

The findings, by researchers with Virginia Commonwealth University in Richmond, also indicate women are more susceptible than men.

"This study indicates that genes may play a larger role in the development of insomnia symptoms for women than for men, providing some of the first formal evidence for sex differences in an adult sample," said Mackenzie Lind, a doctoral candidate at the Virginia Institute for Psychiatric and Behavioral Genetics at VCU. "Given the evidence for sex differences, it may be useful to specifically target females for sleep interventions."

According to the American Academy of Sleep Medicine, occasional insomnia strikes one in three Americans and chronic sleeplessness affects about 10 percent of adults.

For the study, published in the September issue of the journal Sleep, VCU researchers tracked the medical records of approximately 7,500 twins who were surveyed about insomnia.

The study was funded by the National Institutes of Health.