It all started with boys wearing pink or red because the colors were seen to indicate strength, while girls wore blue because they were “flighty” like the sky.
A 1918 editorial called “Pink or Blue” wrote:
“There has been a great diversity of opinion on the subject, but the generally accepted rule is pink for the boy and blue for the girl. 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.”
But we’ve come a long way since then – about 100 years later – and those colors don’t mean a think anymore – or shouldn’t.