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