If one parent is a carrier of the cystic

fibrosis gene, while the other parent does

not carry the allele- - Can their child have

cystic fibrosis? Explain why

An individual must inherit two non-functioning CF genes - one from each parent - to have CF. If both parents are carriers there is a 1 in 4 (25 percent) chance that both will pass on the non-functioning gene, which would result in a pregnancy affected with cystic fibrosis.