Babies born in the autumn may be more prone to asthma, a large new study has found. Researchers say that children born about four months before the height of the winter cold and flu season have a 29 percent greater risk of developing the disease than kids born at other times of the year. Experts say this could mean that asthma is triggered by common winter viruses such as respiratory syncytial virus, or seasonal allergies, particularly in children who are genetically predisposed to the disease.