Asthma is an increasingly common immune disorder affecting 7.3% of all Americans and accounting for 14.2 million physician office visits yearly. Like other allergic diseases, asthma is caused by sensitization to environmental allergens leading to chronic airway inflammation and obstruction. Since the prevalence of asthma has risen rapidly over the past century coinciding with rapid changes in our lifestyles, environmental (rather than genetic changes) are thought to be responsible for this increase. Furthermore, like many other immune-mediated diseases, asthma is associated with notable gender disparities. Investigators at the cWIDR are investigating how the microbiota–the collection of microorganisms colonizing our bodies’ surfaces–may predispose to allergy.