Pink and blue became girl and boy colors because of marketing trends. ... A second study from 1994 suggested the color pink was associated with positive reactions like happiness or excitement.

Blue wasn't just "for boys"—blue was the most popular color for both age and gender groups. Whether we were testing a 10-year-old girl or a 48-year-old man, blue consistently emerged as a favorite.

Getting pink jerseys bearing Messi’s name and No. 10 into the market, Southard said, immediately became Adidas’s “No. 1 priority, globally.” Frisco, Texas. Logan Riely/Getty Images ...