Color-blindness is a recessive, sex-linked (X-linked) condition. A woman with normal vision, whose father is color-blind and whose mother is not color-blind, marries a man who is not color-blind. What is the probability that a son born to this couple will be color-blind?
(Hint: start by figuring out what the genotypes of the man and the woman must be. The best starting place is with the woman's parents.)!