A color-blind woman mates with a male with normal color vision Which of these results would indicate that color blindness is caused by an X-linked recessive allele?

Answer 1

All the sons would be color-blind and none of the daughters are color-blind.

Answer 2

If the couple has a color-blind son, it would indicate that color blindness is caused by an X-linked recessive allele. This is because sons inherit their single X chromosome from their mother, who carries the recessive allele for color blindness but does not express it due to her second X chromosome providing the normal color vision gene.