First lets go over the genes:
There is something called Dominant genes, that beat the recessive gene.
So: When a baby is born, genes from the parents come,
Say both of the parents give Recessive Genes, than the child will get that trait, but if one parent gives the child Recessive Gene, while the other gives a Dominant, the child will get the Dominant Trait,
In this case:
Dominant is Brown Hair, while Recessive is Blond hair. So, the point is there is less blonds and more brunettes.
So why does the media tell us Blonds have more fun?
Well, in movies, the blond girl is always the one that gets what she wants, is rich, has all the guys and so on.
So, this is telling women that "You will have a better life if you are Blond" So, since there is less Blonds, the Darker haired Women are more likely to get their hair dyed blond so they get this "Life."
See the point of the Blonds have more fun thing? The Point is hair dye=Money.
Because its also harder and more expensive to dye your hair blond, than it is to dye it darker. But if the media was really smart they would make it:
Reds have more fun! Since Red hair is even rarer.
To Let you know, the whole Blonds have more fun thing is a lie. Come on? How can the color of your hair determine how much fun you have?
For a list of Recessive and Dominant Genes:
http://www.blinn.edu/socialscience/LDThomas/Feldman/Handouts/0203hand.htm
