Cystic fibrosis (cf) is caused by a recessive allele. a couple who do not have cf have a child that has cf. what is the probability that if they have another child, that the child will be heterozygous for cf?
Answer: 50% but some times that child be comes a carrier. it is hard to explain even for me. i have it and i only know a little, so to help you out, here is an image.
