Hemophilia is a sex-linked recessive gene that causes a blood disorder. What are the chances that the daughter of a normal man and a heterozygous woman will have hemophilia?
A) 75%
B) 100%
C) 50%
D) 0%
E) 25%

Question

Quizplus · Accepted Answer

Since hemophilia is a sex-linked recessive trait, a daughter would need two copies of the gene to express the disorder. A normal man cannot pass on the hemophilia gene, and a heterozygous woman has only a 50% chance of passing on the affected X chromosome. However, since the daughter can only inherit her father's normal X chromosome, she cannot be affected, making her chances of having hemophilia 0%.

Hemophilia Is a Sex-Linked Recessive Gene That Causes a Blood