Quartz has a neat article on the origin of those ubiquitous pink and blue striped blankets for newborns. Note that when the blankets were introduced, the pink and blue combination was considered suitable for all babies. This is consistent with my research on the 1950s. It was the most popular color scheme for birth announcements and baby cards, in addition to being a common feature of newborn clothing. Imagine the outcome if they had been developed in the 1990s!