The traditional view of the mainstream military is anti-gay. It has always been that way. Knowing this is the case, if a homosexual wants to serve in the military and come out openly, who are we to stop him or her? It may very well be a death sentence but each individual has a right to make that decision for him or herself.
Anyone who passes basic training should be allowed to fight, regardless of sexual orientation. Homosexuality was long misunderstood as a disease, but instead it is now considered normal. Gays should be allowed to serve openly because the Armed Forces aren't about sexuality, but are instead about winning wars and fighting for the common defense.