A Type of Muscular Dystrophy Shows Sex- Linked Recessive Inheritance

Multiple Choice

A type of muscular dystrophy shows sex- linked recessive inheritance. Affected persons usually die by the age of 20. Suppose that a boy with the disease lives long enough to marry a woman heterozygous for the trait. If they have a son, what is the probability that he will have the disease?

A) 0%
B) 25%
C) 50%
D) 75%
E) 100%