"If I thought they might be right, then we would've dismissed the charges," the prosecutor said. "You've heard the maxim that the simplest explanation is most often the correct one? To me, this kid had all the classic symptoms of shaken baby. That just seemed to be the easiest explanation."

In the eyes of Morton and Hehmeyer, the hospital not only made a mistake and accused a parent of the unthinkable, it did so twice.

"What angers me about this story is that it happened at Geisinger, where it had happened once before," Hehmeyer said. "And what angers me is that the D.A.'s Office did not let him off. They offered him this choice which was not a choice. He lost two years of his life."

Bleeding disorders are uncommon, but emergency-room physicians are supposed to keep them in the back of their minds.

Hamory, Geisinger's chief medical officer, doesn't dispute that Lucas had certain symptoms that an underlying disease can cause. Yet despite the results of the PIVKA test, he said, the symptoms as a whole spelled abuse.

"It's the constellation of findings," Hamory said.

Most hospitals rarely use the PIVKA test. But Turkewitz, president of the state pediatrics chapter, said he thought Morton's efforts would cause it to become more standard.

"We're learning more and more about the subtleties of vitamin K," he said. "The message is: Every case, you really have to approach it with an open mind."

Medical science is forever shifting, and the answers are not always clear-cut. In forensic science, specifically, research has called into question techniques once unanimously accepted: eyewitness accounts, lie detectors, analysis of arson scenes.

But the judicial system doesn't wait for the messy process of science to reach its conclusion. No one can wait that long, because it never ends. Instead, society requires that science render a yes-or-no answer on the spot. Here, the question was whether science could spare a young family's anguish.

Unfortunately for Lisa and Alejandro, the answer was no.