The biological parents of a child with CF (cystic fibrosis) come to you to know about the chances of their future children with the same disease. What would you say to them?

The key is A. There is a 1:4 chance that your future child will have this disease. [It is autosomal recessive disease. As one child is affected both parents are carrier. So in this case next child will be normal in 1:4 case, carrier in 1:2 cases and diseased in 1:4 cases].