The most common form of color blindness is red-green color blindness, and the mode of inheritance is X-linked recessive. Males have only one X chromosome, so they only need one color blindness gene to show color blindness, while females have two X chromosomes, so they need a pair of disease-causing alleles to show the abnormality. The laws of inheritance are as follows: i. If the father is colorblind and the mother is normal, all boys born are normal and all girls are gene carriers. Second, if the father is normal and the mother is a gene carrier, half of the boys born are colorblind and half of the girls are gene carriers. If there is only one male and one female, they may both be normal, or the male may be colorblind and the female is a gene carrier. If the father is normal and the mother is colorblind, all the boys born are colorblind and all the girls are carriers. If the father is colorblind and the mother is a carrier, half of the boys born are colorblind and half of the girls are colorblind and half are carriers of the gene. V. The father and mother are both color-blind, and all the children born are color-blind.