Question

If sophie conceives a child, and the father neither has cystic fibrosis nor is a carrier, what are the chances that the child would have cystic fibrosis?

Answer 1

A person must inherit two copies of a defective CF gene -- one copy from each parent -- to have the disease. People who inherit only one copy are considered CF carriers and do not have the disease, but they can pass their copy of the defective gene on to their children.