Cystic fibrosis (CF) is a multisystem disease affecting the digestive system, sweat glands, upper and lower respiratory tracts, and the reproductive tract, but progressive lung disease continues to be the major cause of morbidity and mortality . CF is characterized by abnormal transport of chloride and sodium across the respiratory epithelium, resulting in thickened, viscous airway secretions . Over a highly variable time course ranging from months to decades after birth, individuals eventually develop chronic infection of the respiratory tract with a characteristic array of bacterial flora , leading to progressive respiratory insufficiency and eventual respiratory failure. The rate of progression varies widely, depending in part on genotype (including gene modifiers) as well as environmental factors. Registry data from CF Centers in the United States, Canada, and Europe indicate a median survival of about 41 years . Females with CF appear to have higher morbidity and mortality than males . This "gender gap" is modest but consistent across many populations and is hypothesized to be due to the pro-inflammatory effects of estrogens.