Originally, at the moment of the formation of Stargate Command in 1997, there were nine SG teams created, from SG-1 to SG-9. At present there are at least twenty-five of them, up to SG-25. The majority of the teams consist of members of the U.S. Military like the United States Air Force, some Marines, civilians and United States Army soldiers, as well as teams from other nations like the Russian Federation. A few alien beings have also been allowed to join. (SG1: "Children of the Gods", "Uninvited")