A study of 132 adolescent twins with a mean age of 12 years – 66 monozygotic and dizygotic pairs – found that there is a strong genetic influence on the sleep-wake patterns of children. Additive genetic factors accounted for 65 percent of the variance in total sleep time and 83 percent in sleep onset latency. In contrast, a predominant influence of shared family environment was found on the timing of sleep: 67 percent for sleep start time and 86 percent for sleep end time. The study is published in the November issue of the journal SLEEP.
