A growing number of medical experts and law enforcement officials are reversing testimony that put parents behind bars. But they face an uphill battle.

Thousands of caregivers have been arrested since the early 1980s based on the medical belief that young children hospitalized with three symptoms — brain swelling, bleeding in the brain and bleeding at the back of the eyes — must have been forcefully and deliberately shaken. Many doctors and pediatric associations remain steadfast in the view that those symptoms help prove that a child has suffered what is now often called “abusive head trauma.”

But a growing number of medical and forensic experts say the diagnosis is too definitive, particularly in the absence of other signs of abuse. Accidental falls from changing tables can similarly jostle the brain. Clotting disorders and other illnesses can also cause brain bleeding. While some babies are undoubtedly shaken by overwhelmed caregivers, which can cause life-threatening brain damage, these scientists say it isn’t enough to look only at three symptoms before they draw conclusions.

In a major victory for shaken baby syndrome skeptics, New Jersey’s Supreme Court recently agreed, affirming a lower court ruling that likened the diagnosis to unreliable “junk science” and barring expert testimony about it from two upcoming trials. The 6-1 ruling, closely watched by accused caregivers and their attorneys nationwide, could shift how courts weigh shaken baby evidence.