The University of California, Santa Barbara, has issued a study saying blonde women - even those who have dyed their hair - are more aggressive than redheads or brunettes in getting their own way.  Apparently this aggression stems from blondes being used to men generally seeing them as more attractive and giving them more attention.

Further details of this study can be found on http://www.dailymail.co.uk/femail/article-1243964/Blondes-aggressive-brunettes-attract-male-attention.html