The male’s father was colour blind with genotype XcY and mother had no gene for colour blindness with genotype XX, thus genotype of male would be XcY×XX XY The female’s father was also colour blind with genotype XcY and mother had no gene for colour blindness, thus with genotype XX, thus genotype of female would be XcY×XX XXc On crossing this male and female: XY×XcX Their daughter can have genotype XX or XXc, thus she could be normal or carrier, but the probability of she being colour blind is 0%.