Question

In humans, the condition of color blindness is caused by a recessive allele located on the X chromosome. A color-blind woman marries a man with normal vision. What is the probability that their son will be color-blind?

• A. \( 0\% \)
• B. \( 25\% \)
• C. \( 50\% \)
• D. \( 100\% \)

Hint:

For sex-linked traits, remember that males express the phenotype of the single X chromosome they inherit. If a mother is homozygous recessive for a sex-linked recessive trait, all her sons will express the trait, as they inherit her recessive X chromosome.