Military Service by Transgender Individuals: Memorandum for the Secretary of Defense [and] the Secretary of Homeland Security, August 25, 2017 [open pdf - 190KB]
"Policy. (a) Until June 2016, the Department of Defense (DoD) and the Department of Homeland Security (DHS) (collectively, the Departments) generally prohibited openly transgender individuals from accession into the United States military and authorized the discharge of such individuals. Shortly before President Obama left office, however, his Administration dismantled the Departments' established framework by permitting transgender individuals to serve openly in the military, authorizing the use of the Departments' resources to fund sex-reassignment surgical procedures, and permitting accession of such individuals after July 1, 2017. The Secretary of Defense and the Secretary of Homeland Security have since extended the deadline to alter the currently effective accession policy to January 1, 2018, while the Departments continue to study the issue. In my judgment, the previous Administration failed to identify a sufficient basis to conclude that terminating the Departments' longstanding policy and practice would not hinder military effectiveness and lethality, disrupt unit cohesion, or tax military resources, and there remain meaningful concerns that further study is needed to ensure that continued implementation of last year's policy change would not have those negative effects."
Federal Register: http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR
Federal Register (August 30, 2017), v.82 no.167, p.41319