Don’t ask don’t tell is the current military policy concerning homosexuality in the armed forces.
It passed as law in Senate (63 to 33) on September 9, 1993 and in the House (301 to 134) on September 28, 1993. Basically, it states that the armed forces can continue to remove homosexuals from its ranks once it becomes known that someone is gay. The reasoning is that once it is know it is a risk to command, because some people will not serve with a homosexual. However the military can no longer ask you directly your sexual orientation.
There has been much debate over this topic. Those who are for gay rights believe that they should be able to serve openly if they wish. Others don't believe they should be allowed to serve at all. I personally would feel fine about shooting down the enemy on a battle field with someone who was homosexual, but living in the tight living conditions might be strange. But not something that would be a risk to command.