There’s a scene in the 1917 film Poor Little Rich Girl when Mary Pickford, the adult actress portraying the 11-year-old title character, is punished for naughtiness by being forced to turn in her frilly dress for a suit of boys’ clothing. Standing before a mirror, she pouts at first, then sticks her hands into her pockets—and discovers what a fine, freeing, and powerful thing menswear can be. Pickford’s face radiates joy as she rises on her tiptoes; it’s a glorious moment.
By then the pocket had,...