The colors pink and blue are associated with girls and boys respectively, in the United States, the United Kingdom and some other European countries.
Originating as a trend in the mid-19th century and applying primarily to clothing, gendered associations with pink and blue became more widespread from the 1950s onward. Since the 1990s, these gendered associations have also increasingly applied to toys as well, especially in the case of pink toys for girls. Additionally, a pink ribbon is a symbol of breast cancer awareness, and the two colors are used at gender reveal parties.
Despite popular belief—including from various academic and popular sources—a reported "pink–blue reversal", wherein the gendered associations of both colors were "flipped" sometime during the 20th century, most likely never occurred, and instead is likely to have been a misunderstanding of earlier reporting.