People with Cystic Fibrosis have inherited two copies of the defective CF gene: one copy from each parent. Both parents must have at least one copy of the defective gene and they are called carriers.
Each time two CF carriers have a child, the chances is about 25% (1 in 4) the child will have CF. More than 30,000 people are living with cystic fibrosis and more than half of the CF population is age 18 or older.
About one in every 35 person in the world is a symptomless carrier of the defective CFTR gene.