When can a color-blind man have a color-blind grandson?

Color blindness is a hereditary disease that manifests itself in a partial (complete) inability to determine the colors of surrounding objects. Women act as carriers of the disease. Thus, if a man is color blind in a couple, then their children will not get color blindness, while there is a threat that the couple’s grandchildren will get color blindness if the couple’s daughter acquires the color blindness gene and subsequently gives birth to a son with this disease.