WHat contributes to higher rates of asthma?

Good question. The experts are not really sure about why the rise in asthma is happening but the two theories are that things are "cleaner" than they used to be and children are not exposed to possible allergens and then the second theory is that there are just more allergens in the air and environment Here is a nice discussion - without a clear cut answer :) http://www.healthline.com/health-news/children-allergies-and-asthma-on-the-rise-110813.