Why do males prefer females with blonde hair? I would like to know why males prefer blonde women.
Ellis (1974) thought that men prefer rotund features in women and that blonde hair creates such a roundish upper body shape because the blonde hair, which is close in color to (a white woman's) skin, would blend with the skin.

In his famous book, The naked ape, Desmond Morris (1967) documented that men prefer adolescent features. In his opinion blonde hair serves as a secondary sexual characteristic, because skin and hair tends to be lighter in infants than in adults.

One recent study supports this view: Studying Polish men, Sorokowski (2008) found that those men rated blonde women as younger. Since the men also rated younger women as more attractive, Sorokowski concluded that blonde hair may serve as an age cue for men. Consequently, in a second study, Sorokowski found that middle aged women are more likely to die their hair blonde. Younger women already are young, so they don't need that cue to appear attractive. Only middle aged blonde women were rated more attractive than their non-blonde same-age peers. Young women of all hair colors appear equally attractive.

Youth is associated with fertility and health. Ramachandran (1997) proposes a theory that explains how blonde hair can signal health: blonde hair is usually found in women with light skin, and light skin better allows the detection of skin color changes that are symptoms of illness and infestation with parasites. According to Ramachandran, blonde hair simply signals that the man can more easily check if the woman is healthy.

Rowell and Servedio (2009) propose that male preferences help avoid competitive pressure from other males. According to this view it does not matter so much that maybe men prefer blonde women on average. The important finding is that most men fall into groups liking different kinds of women – differentiated not only by hair color but by complex combinations of traits – and therefore do not compete with each other. (Many men here will probably be able to testify that they found women unattractive that a male friend found attractive. In effect they could remain friends, because they liked different women and did not have to compete with each other.)

There is lots more. These are just the first hits from a quick search. An interesting article in the Guardian summarizes some more research: http://www.theguardian.com/science/2010/jun/04/men-blonde-women-attractive



Sources:


Ellis, H. (1974). Man and woman: A study of secondary sexual characteristics. New York: Amo Press.
Morris, D. (1967). The naked ape. New York: Dell.
Ramachandran, V. S. (1997). Why do gentlemen prefer blondes? Medical hypotheses, 48(1), 19-20.
Rowell, J. T., &amp; Servedio, M. R. (2009). Gentlemen prefer blondes: the evolution of mate preference among strategically allocated males. The American Naturalist, 173(1), 12-25. Available online at www.jstor.org/discover/10.1086/593356
Sorokowski, P. (2008). Attractiveness of blonde women in evolutionary perspective: Studies with two Polish samples. Perceptual and motor skills, 106(3), 737-744. Available online at http://www.amsciepub.com/doi/abs/10.2466/pms.106.3.737-744