In a recent Vox post, Katherine Hicks stated,
. . . If [S.2943, the Senate version of the 2017 National Defense Authorization Act] becomes law, women turning 18 on or after January 1, 2018, will have to sign up for the Selective Service System.
Men have been required to do so since the Civil War, though the Selective Service System has only existed in its current form since 1980.
The italicized phrase, however, oversimplifies the history of American draft registration, and seemingly – but erroneously – implies that male draft registration has been continuously required from the Civil War until today. In fact, during the Civil War, the federal government probably did not require men to register for the draft. During both world wars, the United States required men to register, but initially only on certain days. Continuous registration, with men having to register upon turning 18, only began in World War II.