Comfort Women

If we look at the comfort women issue from a utilitarian perspective, it could be seen as morally permissible.  It could be argued that that the good was maximized while the suffering was minimized in this case.  Comfort women were argued as necessary by the Japanese Imperial Army because it would discourage soldiers from raping civilians.  They believed that it would contain the spread of venereal disease among their soldiers.  Comfort women were also used because the military thought it would prevent military secrets from leaking out.  The brothels were securely controlled by the military and isolated from any outside contact, stopping the revelation of military secrets.
If the use of comfort women prevents soldiers from raping civilians it could be seen as morally permissible. The 200,000 comfort women who were used could be way less than the number of civilians that soldiers could have potentially raped if comfort women were not at their disposal.  These soldiers could have also spread venereal diseases to these citizens, therefore the use of comfort women maximizes the good and minimizes the suffering.