Research has shown that children with mothers that live in sunnier locations during their second trimester are significantly less likely to have asthma than other children.

A consortium of researchers from the University of Kansas, Harvard University and the Massachusetts Institute of Technology analyzed data from both hospitals and national surveys to determine sunlight exposure for the mothers. Increased exposure to sunlight increases levels of natural vitamin D.

“We’re not looking at sunny places versus non-sunny places,” clarifies David Slusky, a University of Kansas assistant professor of economics. “We looked at the relative differences of the level of sunlight at a particular place at a particular time of year.”