"Gay troops have been showering alongside straight troops for quite a while. The same is true of professional athletes, students at dorms with communal showers, and gyms across the country."
Yes, this is obvious.
Those who are harping on the shower issue have lost track of the pervasive reality that we can't know and can't police what is in another person's mind — and that people frequently think sexual thoughts. It's utterly routine to encounter people who are thinking about having sex with you. Sometimes these are people you would regard as acceptable sexual partners and sometimes they're not. So what? It's insane to let that bother you. If they don't say anything or do anything or act out in any way, it's nothing to us. If your ability to go about doing what you need to do is undermined by worrying about other people's sexual thoughts, then you are abnormal. It's ironic for the people who think homosexuals are abnormal to believe that heterosexuals are abnormal.