*Sigh* ... even a great scientist like Darwin could do stupid research. :( To begin with, his hypothesis is wrongly formulated and/or based on wrong assumptions. Finding a mate (to have sex with) is not the same as marrying. Everybody knows that no matter what colour your hair is, it is much easier for a female to find a partner for sex. Secondly, while talking about marriage, he doesnt take into consideration the social structure of the society and the economical conditions, as well as traditions and custom. Rich usually would prefer to marry rich, even if they fancy a relatively poor blond. Thirdly, Darwin wrongly assumes that men are the choosers, and women are passively waiting to get chosen. And fourthly, regardless of the sex, if a blond and a dark-haired procreate, theit child would most probably be dark-haired too, we know that the "dark"-gene usually dominates. So even if all the blonds are married, it doesn't garantee that they produce more blonds.