Answer:
50%
Explanation:
Let the allele for red-green color blindness be represented by c.
Normal vision woman whose father is color-blind will be [tex]X^CX^c[/tex]
Color-blind male will be [tex]X^cY[/tex]
[tex]X^CX^c[/tex] x [tex]X^cY[/tex]
Progeny: [tex]X^CX^c, X^CY, X^cX^c, X^cY[/tex] (See the attached image)
Out of the 2 male progeny, 1 is affected for color-blindness while the other is not affected. This gives a 50% probability that a son of the couple will be color-blind.
