Suppose you are a genetic counsellor, and a man and woman come to you with concerns that if they have a child together, it could have cystic fibrosis. Also suppose that genetic tests reveal that the woman is a carrier for cystic fibrosis but the man is NOT. Which of the following is the best advice you could give them?

Question

Quizplus · Accepted Answer

Cystic fibrosis is an autosomal recessive disorder, meaning that a child must inherit two copies of the faulty gene (one from each parent) to develop the condition. If one parent is a carrier (has one copy of the faulty gene) and the other parent is not (has no copies of the faulty gene), their children cannot inherit two copies of the faulty gene and therefore cannot develop cystic fibrosis. However, each child has a 50% chance of inheriting the single faulty gene from the carrier parent, making them a carrier as well.

Suppose You Are a Genetic Counsellor, and a Man and Woman