What color is the offspring of a purple and green flower?

the father in the first generation probably had the recessive colorblind trait in his x chromosome. if he and his wife both had the colorblind trait, even if she had 1 recessive and 1 dominant, then that trait would be passed on to their kids.

(since you didn't attach the family tree this is just an assumption)

answer; i believe that the correct answer is ; males are hemizygous for the x chromosome;