Interesting question. Colour blindness is usually genetic in origin. It has a greater occurrence in males than in females, occurring in 8% of the male population as against only 2 % of the female population. This is because males are more prone to inheriting an X-linked mutation since they have only have X chromosome(XY), whereas females have two(XX). When colour blindness is caused by mutations on the X choromosomes both male and female offspring have a 50% chance of being carriers of colour blindness. Nature deals with mutation by carrying the healthy copy to the next offspring. Males only have one X chromosome so they are more prone to receive the X mutations from their mothers. Females have two and one of the copies can silence the mutation, but this is not possible in males who have only one X choromosome and no other to neutralize the mutation. Hence males are more prone to inheriting colour blindness from their mothers than females are and this is why it is more prevalent in males than in females.