Michigan's prison system is defending against a major lawsuit that claims guards and other employees failed to prevent the sexual assault of male inmates under 18 who were housed with adults.

After more than a year of litigation, the young inmates have made some important victories. Washtenaw County Judge Carol Kuhnke has agreed to make the case a class-action and also declared that state civil rights protections apply.

The lawsuit says teens were forced to engage in sex acts with adult prisoners and staff. The attorney general's office says it doesn't believe there was "rampant" abuse as alleged.

Males under 18 now are housed away from adults. In 2009, the state agreed to a $100 million settlement with female prisoners who said they were assaulted by male staff.