Josh and I are almost positive Alex is color blind. There are different variations of color blindness and we think she is red-green color blind. Alex has known all of her colors for some time now and can easily identify all colors...except red. For a while, she would just guess random colors and lately, red is always green. At Alex's next doctors appointment, we will discuss it with him. We are still a little baffled because we do not know of any color blind people in our family (it's hereditary) and it is very uncommon for a female to be color blind. Only about 0.4% of women in the US are color blind, where 7% of males are. Apparently for a female to be color blind, both mother and father have to have the same defect on their X chromosome.
We did a little research to try and figure out what a red-green color blind person sees and here is what we found.
A Braeburn apple and a Granny Smith.
The second row shows how a color blind person would view the same apples.

If we tell Alex something is red, she will tell us red next time we ask her, but I think that is just because she remembers it. If we introduce new red items, she always identifies them as green.
If she is in fact color blind, I already told Josh we are completely redoing our Christmas tree. We have all red ornaments. Alex is already showing a pure love for all things Christmas and I want her to be able to enjoy and appreciate our tree as much as we do!