<prompt> A normal couple has one daughter affected with Cystic fibrosis. They are now planning to have another child. What is the chance of siblings being affected by the disease -0502575  <response>: Ans. c 25Ref: Robbins 9thpg 141; 8thpg 141Cystic fibrosis is an autosomal recessive condition.If one daughter is affected, genotype will be ccTherefore, both parents must have been carriers of cystic fibrosis.Thus each child other sibling has a 1 in 4 25 chance of being affected. 