You're ignorant for so many reasons with this post.
First off, gay men have been showering with straight men since showers have been around in the military and out. Are there situation that arise where there is some sort of sexual misconduct that arose from it? Of course, but there are many more incidents of straight people involved in sexual misconduct. Hell, hazing/abuse happens all the time. Especially with straight boys/men, and it's not uncommon for it to end up sexual in some way. I fully would support co-ed showers and dorms. That said, it's not reasonable in reality. In theory it should be like Starship Troopers where we all shower together. In reality that's not going to happen.
Your last paragraph really shows how much of a homophobic idiot you are. The military isn't exactly having a "surplus" of troops. While it's not at the draft levels, it's also not that we are turning people away due to no need for them. Show me any kind of factual evidence that ending DADT would create problems, and please explain what kind of "problems" they would bring. You should look up the DADT policy. It allows gays in the military, provided they aren't openly gay. Guess what? That means almost without a doubt you have showered, bunked, trained with, and work with at least 1 gay person in your career. How many times have you been raped/molested/hit on/sexually harassed by a gay man?
Or, how about this. We allow gays to openly serve, and keep gender specific showers/barracks. There are valid reasons (although it might not be "fair") to keep men and women segregated believe it or not. While most of the same arguments could be made for gays, there is one that couldn't. Gays having sex never equates to pregnancy.