A man whose father was colourblind marries a woman, who has a colourblind mother and normal father. What percentage of male children of this couple will be colourblind?
(3) As colourblindness is a recessive genetic disorder, the gene responsible for it is present on 'X-chromosome'. The man whose father was colourblind is normal (XY). But the woman whom he marries can be a carrier to this disease, as her mother was colour blind XcXc with a normal father (XY). Thus, in this case, the percentage of male child to be colourblind is 50%.