Cystic fibrosis is a recessive disease … an individual must have 2 copies of the recessive allele “c” to have the disease. What are the chances that a Cc mother and a CC father can have a child with cystic fibrosis? [Hint: make a Punnett square to figure this out.] A. 100% B. 75% C. 25% D. They can’t have a child with cystic fibrosis