Why is pink a girl color and blue a boy color? In the 19th Century, pink used to be associated with boys, since it was a stronger, more decided color. Blue, on the other hand, was regarded as a girls’ color, because it was considered dainty. It wasn’t until the 1940s that marketers started to switch it around. Jeanne Maglaty has a great article about this in Smithsonian Magazine, called “When did Girls Start Wearing Pink?” This is part of a complete episode.