Was the "don't ask, don't tell" policy an act of discrimination against homosexuals?

[ClumsyClumsy:]]

IT doesn't make sense why the government would want to discriminate against men from joining the army- the more the better,right? I have heard a more logical reasoning behind this that this policy was set up so that gay men would not perform sexual intercourse while in the army (when they are suposed to training, rest, etc). So was the "don't ask, don't tell" policy an act of discrimination, or an act to prevent disorder and maintain effiency of training?