Life on board nuclear submarines might potentially get interesting.
I personally think that there will be more disruption from adding women to subs, not open gays. Submariners are a special brand of crazy anyway, and we police our own quite well. On my boat, we had two sailors who were known or suspected to be gay. One of them was a good sailor, and not flouncy; he was part of the crew. The other was annoying, acted queer, and not a good sailor. He didn't last long.