According to the website „Gender Specific Colors,” it would seem that assigning color to gender is mostly a 20th century trait. It would also seem that at one time, the color associations were reversed when color first came into use as a gender identifier. In fact, this reversal of what we consider „normal” was considered conventional, even in the early 20th century.
„At one point pink was considered more of a boy’s color, (as a watered-down red, which is a fierce color) and blue was more for girls. The associate of pink with bold, dramatic red clearly affected its use for boys. An American newspaper in 1914 advised mothers, „If you like the color note on the little one’s garments, use pink for the boy and blue for the girl, if you are a follower of convention.” [The Sunday Sentinel, March 29, 1914.]
„There has been a great diversity of opinion on the subject, but the generally accepted rule is pink for the boy and blue for the girl. The reason is that pink being a more decided and stronger color is more suitable for the boy, while blue, which is more delicate and dainty, is prettier for the girl.” [Ladies Home Journal, June 1918]
According to Jo B. Paoletti and Carol Kregloh, „The Children’s Department,” in Claudia Brush Kidwell and Valerie Steele, ed., Men and Women: Dressing the Part, (Smithsonian Institution Press, 1989). – In the United States: „The current pink for girls and blue for boys wasn’t uniform until the 1950’s.