The theory that pink is for girls and blue is for boys has been a norm in American society since the 1940s. But before World War II, that wasn't always the case. Baby photos from the late 1800s show both male and female children wearing white frilly dresses. This was a practical decision so that the white clothes could be easily bleached. But even after pastel baby clothes were introduced, there was a lot of variation in what colors were considered gender-specific. According to University of Maryland historian Jo B. Paoletti, author of Pink and Blue: Telling the Girls from the Boys in America, in the early 20th century, the generally accepted rule was pink for boys, blue for girls. It stayed that way until the 1940s, when clothing manufacturers and department stores settled on the opposite color scheme.
Are you pink or blue?