Light pigmentation traits had already existed in pre-Indo-European Europeans (both farmers and hunter-gatherers), and long-standing philological attempts to correlate them with the arrival of Indo-Europeans from the steppes were misguided.
Each of the two forms, however, is pronounced identically.
American Heritage's Book of English Usage propounds that, insofar as "a blonde" can be used to describe a woman but not a man who is merely said to possess blond(e) hair, the term is an example of a "sexist stereotype [whereby] women are primarily defined by their physical characteristics." The OED also records that blond as an adjective is especially used with reference to women, in which case it is likely to be spelt "blonde", citing three Victorian usages of the term.
The masculine version is used in the plural, in "blonds of the European race", Another hair color word of French origin, brunet(te) (from the same Germanic root that gave "brown"), functions in the same way in orthodox English.
The OED gives "brunet" as meaning "dark-complexioned" or a "dark-complexioned person", citing a comparative usage of brunet and blond to Thomas Henry Huxley in saying, "The present contrast of blonds and brunets existed among them." "Blond" and "blonde" are also occasionally used to refer to objects that have a color reminiscent of fair hair.
An alternative hypothesis was presented by Canadian anthropologist Peter Frost, who claims blond hair evolved very quickly in a specific area at the end of the last ice age by means of sexual selection.