From Code Girls, by Liza Mundy (Hachette, 2017), Kindle pp. 76, 81:
Parker Hitt was a champion of women and a believer in women’s intellectual abilities as well as their bedrock stamina. In Europe, Parker Hitt was charged with overseeing battlefield communications for the Army’s Signal Corps. The Americans, British, and French strung phone lines around Europe and needed telephone operators to connect the calls. Switchboard operation was women’s work, and male soldiers refused to do it. French operators were not as adept as American ones, so the Signal Corps recruited U.S. switchboard operators who were bilingual in English and French and loaded them into ships bound for Europe. Known as the “Hello Girls,” these were the first American women other than nurses to be sent by the U.S. military into harm’s way. The officers whose calls they connected often prefaced their conversations by saying, “Thank Heaven you’re here!” Parker Hitt pushed for the Hello Girls to be allowed to prove their competence and courage. They did so, remaining at their posts even when ordered to evacuate during bombing in Paris, and moving to the front lines, where they worked the switchboards during explosions and fires.
The U.S. Navy, meanwhile, was developing its own female secret weapon, as part of a code-breaking operation that, true to the prevailing climate, was kept jealously separate from the Army or any other rival entity. Upon America’s entry into World War I, the country had struggled to quickly enlarge its modest career Navy, and created a men’s naval reserve that permitted civilian men to serve during wartime, often as specialists with expertise in areas such as math or science. Even this influx wasn’t enough, however, and it occurred to Secretary of the Navy Josephus Daniels to wonder aloud whether there was any law “that says a yeoman must be a man.” Remarkably, there was not. Nowhere in the Naval Reserve Act of 1916 did it say that a naval yeoman had to be male. Thanks to that loophole, American women were permitted to enlist in the naval reserves during World War I, and the designation “Yeoman (F)” was created. The move was controversial, even shocking, to the public, but many more women hastened to enlist than the Navy had expected. To the women’s disappointment, they were not allowed to serve on ships (nurses, who were in a different category, could do so) but mostly worked as clerks and stenographers, facilitating the towering stacks of paperwork that the naval bureaucracy generates—the original yeoman’s work. During the first global conflict of the twentieth century, eleven thousand American women served as Yeoman (F)—also called yeomanettes.