Question

Cystic Fibrosis is a genetic disease of the lungs caused by a recessive allele. A man with Cystic Fibrosis marries a woman who does not have Cystic Fibrosis, but her father had the disease. What is the probability of the couple having a child that has Cystic Fibrosis?

Answer 1

If only one of you is found to be a carrier, the chance that you will have a child with CF is very low, although not completely eliminated. If you are both carriers, each pregnancy will have a 1 in 4, or 25 percent chance of being affected with cystic fibrosis.