Women started shaving their legs around the early 20th century. The practice became more common in the United States after the introduction of the first safety razor for women by Gillette in 1915. This was further popularized by the fashion trends of the 1920s, which involved shorter hemlines and sheer stockings, leading to increased leg exposure and the need for smooth legs. Over time, the practice of leg shaving became a social norm in many Western countries. The search results did not provide specific historical information on when women started shaving their legs. However, historical accounts and cultural studies support the information provided above.