History.com: How the Us Civil War Inspired Women to Enter Nursing

Before the American Civil War, the majority of hospital nurses or "stewards" were men. But the war created a medical crisis that demanded more volunteers, and a lot of the people who took up the call were women. Amid this desperate need for medical workers, women began to volunteer as nurses for wounded soldiers. After the war, women continued to work in medicine; and by 1900, they represented 91 percent of U.S. nurses.