Why Can’t My Hair Naturally Grow Neat Colours?

Man, I wish my hair could grow blue naturally like in some sort of utopian science fiction movie. Also I don’t want to dye it. Can science help me out? Surely the plastic surgeons and geneticists, with the marvels of contemporary medicine, are close to developing this technology? Why can’t my hair naturally grow these neat colours?

Science has come far, but not THIS far.

I’ll tell you why. Because the palette of colours with which the human genome paints our heads consists of only four colours. Two types of pigment, eumelanin and pheomelanin, give human hair its colour. Pheomelanin colours hair orange and yellow, while eumelanin colours hair black and brown. All hair types and shade gradations are determined by these four colours. In other words, the only way scientists could possibly make you have natural green hair is to splice in DNA from a troll doll or something.

Source: http://en.wikipedia.org/wiki/Hair_colour