Argument: Gays in the military increase sex-based favoritism
John Luddy. "The Military Gay Ban: Why Don't Ask, Don't Tell Don't Work". Heritage Foundation, Executive Memorandum #359. July 1, 1993 - 2) Professionalism is undermined.
The presence of homosexuals in the armed services threatens the military's highly regarded merit-based system. Sexual attraction encourages special relationships without regard to rank and increases the risk of favoritism. Political activism elsewhere in society suggests that weakening the ban would be followed by quotas and lawsuits if homosexuals were not promoted in representative numbers. This would destroy the cohesion of a military unit, and erode the military's successful merit-based promotion system.