If you had a baby in the year 1900, you would have been told to dress them according to this reversed rule:

Why pink could be for boys and blue for girls

Around 1900, some American clothing guides and retailers recommended the color pairing opposite to the one many people expect today: pink for boys and blue for girls. The reasoning was not a timeless rule. Pink was treated as a stronger, more assertive shade of red, while blue was associated with delicacy and with traditional depictions of the Virgin Mary.

But the advice was far from universal. Families, shops, and publications did not all follow one standard, and baby clothes were often white regardless of a child’s sex. White cotton was practical: it could be bleached and laundered repeatedly, and infants were commonly dressed in long gowns that did not depend on a gender-specific color code.

How the colors switched

The familiar modern pairing took shape gradually during the early 20th century. Retailers and manufacturers increasingly promoted separate colors for boys and girls, but recommendations varied before blue for boys and pink for girls became broadly established in the United States in the mid-20th century. The shift was a change in convention, not a discovery about children’s preferences or a rule that had always existed.

That history is why a baby born in 1900 might have been given pink clothes as the “boy” choice—or might have been dressed in white instead. The colors we now treat as natural signals of gender are the result of changing fashion and marketing, not an enduring tradition.