Perhaps no crime staggers the mind, or turns the stomach, more than the murder of a baby, and so it is not a surprise when law enforcement comes down hard on the presumed killers. Often enough, these are men and women accused of having succumbed to sudden rage or simmering frustration and literally shaken the life out of a helpless infant who would not stop crying or would not fall asleep.

Shaken baby syndrome has been a recognized diagnosis for several decades, though many medical professionals now prefer the term abusive head trauma. It is defined by a constellation of symptoms known as the triad: brain swelling, bleeding on the surface of the brain and bleeding behind the eyes. For years, those three symptoms by themselves were uniformly accepted as evidence that a crime had been committed, even in the absence of bruises, broken bones or other signs of abuse. While many doctors, maybe most, still swear by the diagnosis, a growing number have lost faith. Not that they doubt that some babies have been abused. But these skeptics assert that factors other than shaking, and having nothing to do with criminal behavior, may sometimes explain the triad.

Has the syndrome been diagnosed too liberally? Are some innocent parents and other caretakers being wrongly sent to prison? Those questions, at the complex intersection of medicine and the law, can stir strong emotions among doctors, parents and prosecutors. They shape this first installment in a new series of Retro Report, video documentaries that explore major news stories of the past and their enduring consequences.