Boys in Red

From Two Nerdy History Girls:

In the 18th-19th c., the color red was much more associated with English boys than blue. It was considered a properly masculine color, and one with strong military overtones as well as the color for hunting. As soon as a boy was breeched – dressed in male adult-style clothing instead of the unisex white gowns of babies – bright red usually made an appearance in his wardrobe. Later in the 19th c., when color first was used in infant clothing, pink, as the lesser version of red, was the color for boys, while girls were dressed in pale blue. (For more about gender-dressing by color, see this article from Smithsonian.) (Read more.)