A U.S. Supreme Court ruling and emerging brain research is challenging how the criminal justice system handles juveniles who commit murder and other serious crimes.

Wisconsin juveniles sentenced to life in prison are currently in legal limbo, in part because of a 2012 U.S. Supreme Court ruling that banned mandatory life sentences without parole for juveniles that had committed murder.

A follow-up ruling this year stated the decision should be retroactive, meaning someone who had already received a life sentence without parole should now get a chance to see the parole board or have their sentences reexamined.

Since that decision was made, there are about 68 inmates in Wisconsin who committed murder before turning 16 that are still in a legal gray area.

The Supreme Court ruling addressed mandatory life sentences without parole for juveniles. But Wisconsin laws don't allow such sentencing, making the high court's ruling a bit ambiguous.

"That's one aspect that doesn't apply to the 68 people we're looking at," said Milwaukee Journal Sentinel reporter Cara Lombardo. "Actually, on our list, they not only have mandatory life sentences, but many of them, all but three on the list I was looking at, will be eligible for parole or have already been eligible for parole."

But some criminal justice advocates say Wisconsin's juveniles are in effect suffering from life sentences without parole because the court system under Gov. Scott Walker's administration has significantly cut back on parole hearings.

"We've seen under Walker's administration fewer and fewer people being granted parole," Lombardo said. "So the question is, are these juveniles effectively serving life sentences without parole? And some of their lawyers are starting to ask that question."

Lombardo said some judges offered life sentences to juveniles knowing parole would be an option about a quarter of the way through their time served. That was the case with one juvenile Lombardo profiled whose parole hearing keeps getting deferred.

"So the court's understanding at the sentence might have assumed that (the convicted juvenile) might have been paroled one day," Lombard said.

Developmental brain research is also reforming sentencing laws, said Lombardo. Just last week, Marathon County Circuit Judge LaMont Jacobson sentenced a 16-year-old Wausau boy, Dylan Yang, to 13 years in prison and 17 years of extended supervision. Jacobson said Yang's age was one of many factors considered in his ruling.

"We now know that it is widely accepted that a juvenile's brain, specifically the portion that control impulse control – the portion that is able to stop and think, 'What are the consequences of this action?' – that is still being formed all the way to your twenties," Lombardo said.