8% of men have colour blindness (daltonism). Are you sure you don´t?
Take this simple and free test and find out the answer. Ishihara´s test. Take a look at one sinlge picture and you get the answer.
D. Whitley, K. Mathias, S. Rana, and J. Dzubera. Proceedings of the Sixth International Conference on Genetic Algorithms, page 239--246. Morgan Kaufmann, (1995)