From both parents. CF is an autosomal recessive disorder meaning the infant must inherit a mutated or abnormal copy of the CF gene from both the mother and the father. If both parents are carriers of a CF mutation, the odds of the infant having CF are 1 out of 4 or 25% for every pregnancy.
From both parents. Parents each pass half their ladder like dna to baby, the dna divides lengthwise with half a rung/parent. If half a rung is a dominent gene, the parent has the problem & passes it. If it takes 1 half from each parent to pass, it is a recessive problem & parents are not affected. Cf is carried in an estimated 1/20 unaffected people. A carrier couple can produce carrier/affected or normal kids.