Cystic Fibrosis (CF) Cystic fibrosis or CF is an inherited disease of the secretory glands. Secretory glands include glands that make mucus and sweat. Inherited means the disease is passed from parents to children through genes. People who have CF inherit two faulty genes for the disease — one from each parent. The parents likely don’t have the disease themselves. CF mainly affects the lungs, pancreas, liver, intestines, sinuses, and sex organs.