Persons 17 years of age, with parental permission, can join the U.S. armed services. http://siadapp.dmdc.osd.mil/personnel/MILITARY/ms0.pdf http://frwebgate.access.gpo.gov/cgi-bin/getdoc.cgi?dbname=110_cong_bills&docid=f:s3001pcs.txt.pdf Federal Government Outlays by Function and Subfunction: 1962–2015 Fiscal Year 2011 (Table 3.2)