Many women have served in the United States Navy for over a century. Today, there are over 52,391 women serving on active duty in an array of traditional (administrative, medical, etc.) and non-traditional (aviation, combat systems, etc.) ratings or careers. Like their male counterparts, female sailors are expected to adhere to regulations specific to appearance, grooming, and health and fitness; however some differences exist for example in physical fitness tests due to performance and in relation to pregnancy and parenting provisions created to help support military families.
Women worked as nurses for the Navy as early as the American Civil War. The United States Navy Nurse Corps was officially established in 1908; it was all-female until 1965. After the establishment of the Nurse Corps in 1908 by an Act of Congress, twenty women were selected as the first members and assigned to the Naval Medical School Hospital in Washington, D.C. However, the navy did not provide room or board for them, and so the nurses rented their own house and provided their own meals. In time, the nurses would come to be known as "The Sacred Twenty" because they were the first women to serve formally as members of the Navy. The "Sacred Twenty" were Mary H. Du Bose; Adah M. Pendleton; Elizabeth M. Hewitt; Della V. Knight; Josephine Beatrice Bowman; Lenah H. Sutcliffe Higbee; Esther Voorhees Hasson, the first Superintendent of the Navy Nurse Corps, 1908–1911; Martha E. Pringle; Elizabeth J. Wells; Clare L. De Ceu.; Elizabeth Leonhardt; Estelle Hine; Ethel R. Parsons; Florence T. Milburn; Boniface T. Small; Victoria White; Isabelle Rose Roy; Margaret D. Murray; Sara B. Myer; and Sara M. Cox. The Nurse Corps gradually expanded to 160 on the eve of World War I. For a few months in 1913, Navy nurses saw their first shipboard service, aboard Mayflower and Dolphin.
The increased size of the United States Navy in support of World War I increased the need for clerical and administrative support. The U.S. Naval Reserve Act of 1916 permitted the enlistment of qualified "persons" for service; Secretary of the Navy Josephus Daniels asked, "Is there any law that says a Yeoman must be a man?" and was told there was not. Thus, the Navy was able to induct its first female sailors into the U.S. Naval Reserve. The first woman to enlist in the U.S. Navy was Loretta Perfectus Walsh on 17 March 1917. She was also the first American active-duty Navy woman, and the first woman allowed to serve as a woman in any of the United States armed forces, as anything other than as a nurse. Walsh subsequently became the first woman U.S. Navy petty officer when she was sworn in as Chief Yeoman on March 21, 1917. During World War I Navy women served around the continental U.S. and in France, Guam and Hawaii, mostly as Yeomen (F), but also as radio operators, electricians, draftsmen, pharmacists, photographers, telegraphers, fingerprint experts, chemists, torpedo assemblers and camouflage designers. Some black women served as Yeomen (F) and were the first black women to serve as enlisted members of the U.S. armed forces. These first black women to serve in the Navy were 16 Yeomen (F)—the total would rise to 24—from some of "Washington's elite black families" who "worked in the Muster Roll division at Washington's Navy Yard...." All women in the Navy were released from active duty after the end of the war.