Scroll through the comments and a pattern starts to emerge: the older sibling often rocked blue and green, while the younger leaned into pink and purple. It’s a theory rooted more in cultural patterns ...

But she was so intrigued by that seemingly universal inclination that she began the “Pink and Blue Project,” an ongoing photographic series of the two colors that are most frequently ...

“It’s really a story of what happened to neutral clothing,” Jo B. Paoletti, the author of Pink and Blue: Telling the Boys From the Girls in America, told Smithsonian magazine in 2011.

This pattern was made in three main colors: pink, green, and cobalt blue. While pink and green are valuable, royal blue is ...