Verified answer

Originally, blue was thought to be a magical color that could ward off evil spirits.

Since baby boys were prized, the baskets/cradles were hung with blue ribbon so the evil spirits would not carry the baby boy away (so he wouldn't die .. and a LOT of infants died before they reached the age of 1 year, so this WAS a big fear).

Baby girls? Not worth much. They would grow up to marry and contribute to their husband's family AND you have to pay a dowry to her future husband's family.

Around the late 1800's/early 1900's, when commercialism starting to become popular (the rise of the middle class, with money to spend) all sorts of holidays and occasions were started, as commercial money-makers.

So congratulations cards when someone had a baby, special clothes for the baby, etc ...

well, they already had blue for boys ... so they decided to sell PINK things for baby girls. It was just an arbitrary decision,, this business of pink for girls, and there is no record of what commercial businessman first thought it up.

I hate gender roles