I think that women as well as gays should not be in units that will be anywhere near combat, or on close deployment situations like ships and submarines. Even driving trucks in Iraq, as whats-her-name was.
It's nothing discrimanatory, it's just that around such situations, sex just gets in the way. Doesn't matter with who, or what. Sex with unit members is just too much distraction, and costs too much in unit cohesion, to be tolerated.
BINGo for an astute observation.