A brief history of femininity and the color pink

How it started: Prior to the 20th century, pink actually represented masculinity, Naomi Greyser, a gender studies professor at the University of Iowa, tells Axios. It was more popular among boys because of its close hue to red, viewed as a "strong" color.

• But mostly it was a gender-neutral color that anyone would wear, Greyser says.

State of play: By the early 20th century, however, darker colors became associated with "manhood" because of the tones used in military uniforms.

• Pinks and other pastels then became associated with femininity.

The intrigue: By the 1980s, pink for girls and blue for boys became even more binary when doctors began being able to determine the biological sex of a baby through prenatal testing.

• Marketers and product designers would sell the same products but with different colors, characterizing one for "girls" and the other for "boys."

Between the lines: Now, we're seeing issues like the "pink tax" where universal items marketed towards women cost more, Greyser says.