Sleep like a baby: nature versus nurture

Environmental factors and decisions made by parents are the most important aspects in determining how well an infant sleeps, both at night and during naptime, although genetics cannot be overlooked either, according to a new study published in the journal Pediatrics.

Researchers in Italy worked with 127 sets of identical twins and 187 sets of fraternal (non-identical) twins, all 18 months old. In both groups, each pair of twins was assumed to share the same sleeping environment. Identical twins also have the exact same genes, while fraternal twins share only about half of their genetic makeup.

By comparing the two groups, researchers found that environmental factors were almost entirely responsible for determining whether a child slept in his own bed or with his parents. Genetic factors did play more of a role in how well a child slept through the night, but this was also largely dependent on their environment.

"Most sleep disturbances during early childhood are explained by common shared environmental factors, and behavioral interventions adopted by parents and focused on modifying sleep behavior could contribute to solving sleep disturbances in this age group," conclude the researchers. "However, the influence of genetic factors should not be underestimated."