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 hemophilia. Also suppose that the woman has an X-linked recessive form of hemophilia, but the man does NOT. Which of the following is the best advice you could give them?

Question

Quizplus · Accepted Answer

Hemophilia is an X-linked recessive condition. Since the mother has hemophilia, she has two affected X chromosomes (XX). The father, who does not have hemophilia, has a normal X and a Y chromosome. Male offspring receive an X chromosome from their mother and a Y chromosome from their father, meaning all male offspring will inherit the affected X from the mother and thus have hemophilia. Female offspring receive one X chromosome from each parent, so they will inherit one affected X from the mother and one normal X from the father, making them carriers but not affected by the condition.

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