Hemophilia A is an X-linked recessive disorder.If a normal man marries a woman who is a carrier,what fraction of their sons will have hemophilia?

Question

Quizplus · Accepted Answer

Since hemophilia A is X-linked recessive, a carrier woman (X^HX^h) can pass the affected X chromosome (X^h) to her sons. The normal man (X^HY) can only pass the Y chromosome. Therefore, there is a 50% chance that a son will inherit the X^h from the mother and have hemophilia.

Hemophilia a Is an X-Linked Recessive Disorder