'For example, a June 1918 article from the trade publication Earnshaw's Infants' Department said, “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.”'
http://www.smithsonianmag.com/arts-culture/When-Did-Girls-St... - extract from this:
'For example, a June 1918 article from the trade publication Earnshaw's Infants' Department said, “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.”'