If we denote a cystic fibrosis gene with a c and a disease-free gene with a C (since the disease is recessive), then only a c
c person will actually have the disease. Such persons would ordinarily die before parenting children, but a child can also inherit the disease from two Cc parents (who themselves are healthy—that is, have no symptoms but are "carriers" of the disease). Suppose a child is born to one cystic fibrosis carrier parent and one non-carrier parent. Find the probability that that the child will be a carrier.
