This could be an extremely difficult question if your talking in general since people dye their hair all the time (Mine's dyed right now actually) but if you're talking about natural hair color then I believe that would be red hair. I'm not really sure why, it's a matter of genes I guess.
White and red hair.
A brown pigment to hair is the most common in the world and therefore the most popular as many people have no desire to change the colour of hair they were born with. Hair colour depends upon melanin and this can vary over time.
His Eye Colour Is Hazel And His Hair Colour Is Brown
eye colour, hair colour, language spoken, skin colour and others
Well, a lot of factors contribute to the colour of peoples hair, E.G. Parents hair colour, where they live, etc. I reckon that the same amount of people have brown hair as the amount of people who have blond hair, ginger, red, black or any other colour. I personally have brown hair.
Eye colour or hair colour is an example of a trait that is not a sex chromosome.
ginger is the rarest natural hair colour in celebrities
Rainbow :)
The color of your hair that you are born with
PURPIL is the VERY RAREST colour of grossman aliens
pink =D
brown
Red is rarest-around 25 percent
Well actually the rarest hair and eye color is burgundy (red and purple and some blonde) and grey eyes which i have or purple hair and violet or green eyes.
The most rarest colour is Black!! Black aliens are normally boys. You can tell if it is! :)
Red and White hair colors are the rarest in the world.
The rarest diamond colour is the naturally occurring red colour. All naturally coloured diamonds have a further grade designation on this scale:FaintVery LightLightFancy LightFancyFancy DarkFancy IntenseFancy DeepFancy VividThe Fancy Vivid colour designation is the most expensive grade.Read more, below.
i would say the colour grey