From the summary of Diversity, Inclusion, and Equal Opportunity in the Armed Services: Background and Issues for Congress (Oct. 4, 2017 R44321):
Diversity, inclusion, and equal opportunity are three terms that are often used interchangeably; however, there are some differences in how they are interpreted and applied between the Department of Defense (DOD) and civilian organizations. DOD’s definitions of diversity and equal opportunity have changed over time, as have its policies toward inclusion of various demographic groups. These changes have often paralleled social and legal change in the civilian sector. The gradual integration of previously excluded groups into the military has been ongoing since the 19th century. In the past few decades there have been rapid changes to certain laws and policies regarding diversity, inclusion, and equal opportunity in the Armed Forces. Since 2009, DOD policy changes and congressional actions have allowed individuals who are gay to serve openly with recognition for their same-sex spouses as dependents for the purpose of military benefits and opened all combat assignments to women. On June 30, 2016, DOD announced the end of restrictions on service for those transgender troops already openly serving. However, in August of 2017, President Donald J. Trump directed DOD to (1) continue to prohibit new transgender recruits, (2) review policies on existing transgender sevicemembers, and (3) restrict spending on surgical procedures related to gender transition.