@Ionus,
what is your point...that the sexual dynamics get too complicated and takes away from combat effectiveness?
I know that in Iraq a lot of sex goes on between the male and female soldiers, it is openly known who is sleeping with whom. I also know that the women sign up for this often because they know that they are going to be continually pressured for sex, so they agree to become the girlfriend the the men they would rather be around.....at least this way they get a better deal. Once they have a boyfriend or two the rest leave them alone, because they are spoken for. Not putting out is not much of an option, they could take that road in theory, but in practice it gets hard to do.
The main thing I see is marriages breaking up because the spouses back home eventually find out through the rumor mill. Young females soldiers are particularly unlikely to be able to stay married, as they are usually having sex with at least a few guys. Some are the camp sluts. Re combat effectiveness though I am not convinced that this is a problem. There were never going to be local prostitutes to service the men like there are in Korea or were in the Philippines...this current arrangement might be fine from the armies point of view. Not sure if it is from the womens, who in this age of assumed choice find out that they really have little choice but to spread them.