I have known I was color blind from childhood.  My parents knew it when I told them the neighbors kept their grass nice an red. 

Most color blind people see color it just isn't the same as others see them.  For me a traffic light is red, orange and white.  I'm fine with very distinct primary colors, it is when you start to mix them that I have a problem. 

By the way, I really appreciate it when companies pick color schemes like red on green.