pasted from AHD:

USAGE NOTE: It is usual in English to treat blond as if it required gender marking, as in French, spelling it blonde when referring to women and blond elsewhere. But this practice is in fact a relatively recent innovation, and some have suggested that it has sexist implications and that the form blond should be used for both sexes. There is certainly a measure of justice to the claim that the two forms are not used symmetrically. Since English does not normally mark adjectives according to the gender of the nouns they modify, it is natural to interpret the final -e as expressing some additional meaning, perhaps because it implies that hair color provides a primary category of classification for women but not men. This association of hair color and a particular perception of feminine identity is suggested in phrases such as dumb blonde and Is it true blondes have more fun? or in Susan Brownmiller's depiction of Hollywood's “pantheon of celebrated blondes who have fed the fantasies of men and fueled the aspirations of women.” The corresponding masculine form blond, by contrast, is not ordinarily used to refer to men in contexts in which hair color is not specifically at issue; there is something arch in a reference to Leslie Howard, Robert Redford, and other celebrated blonds. See Usage Note at brunette.

(well, this begs the question doesn't it?! :P)