In October, Cara Delevingne was photographed in Paris wearing a navy sweatshirt that read “The Future Is Female” in clean white text. The same month, Ms. Delevingne’s girlfriend, the musician Annie Clark (a.k.a. St. Vincent), wore the same shirt, paired with a white Chanel bag, to the Chateau Marmont in Hollywood.

The $50 sweatshirt (also available as a $30 T-shirt, baby onesie and enamel pin) has become a sensation on Instagram and Tumblr, inspiring fans to carve the design into pumpkins, render it in needlepoint and dress small children in it. The sweatshirt isn’t the product of some nebulous corporate slogan. Indeed, it has a radical feminist history behind it.

The original “The Future Is Female” T-shirt design was made for Labyris Books, the first women’s bookstore in New York City. The photographer Liza Cowan took a picture of Alix Dobkin, her girlfriend at the time, wearing it in 1975. The photograph was done for a slide show she was working on.

“I was just beginning to be a photographer, and asked five friends if I could do a before-and-after story on how a woman’s look can change over the course of her life as she matures and comes out,” Ms. Cowan said from her home in Burlington, Vt.