In Western culture, the practice of assigning pink to an individual gender began in the early 1900s. An article in the trade publication Earnshaw’s Infants’ Department in June 1918 stated: “The generally accepted rule is pink for the boys, and blue for the girls. 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.” Up until the 1940s, pink was considered appropriate for boys because it related to the colour red which was considered the more masculine and decided colour. Blue was considered appropriate for girls as it was the more delicate and dainty color, or related to the Virgin Mary who is often depicted wearing the colour blue.
Since the 1940s, the societal norm has been inverted; pink has become considered appropriate for girls and blue appropriate for boys, a “tradition” that has endured to this day. Today’s color dictate was a result of Americans’ preferences as interpreted by manufacturers and retailers. “It could have gone the other way,” says Jo B. Paoletti (Associate Professor of American Studies – Maryland University) who has been researching clothing and gender in America for over 30 years.
Sources: Smithsonian, Wikipedia