It does raise the interesting question as to how we perceive colour, doesn't it?
We do have red/green colour blindness running in our family ..... I'm not affected, but we do have relatives who are. I believe it affects males more than females?
I remember a job interview many years back where us candidates on an assessment day were tested for the condition (flip charts, and what numbers do you see) and I seem to recall there was at least one failure .....