After three decades and thousands of accusations and fractured lives, medical and legal experts are challenging shaken baby syndrome as a diagnosis. And as one family’s saga demonstrates, we can’t wait any longer to get it right.

“Do you have identification?” Robyn asked the woman. No. “A court order?” The largest deputy in the group, maybe six-five, 250 pounds, placed his boot over the doorsill. I’m the court order, he said. They weren’t leaving without Eliana. Robyn scanned the street. At least five patrol cars lined the curb. Every home on the street glowed, the silhouettes of onlooking neighbors framed in the windows. After a 30-minute standoff—the deputies demanding entry into the house, the Felixes refusing—and after tearful phone calls to friends for advice, Robyn woke Eliana in her crib, bundled her, and passed the toddler to the caseworker. The child cried out for Nathan—“My daddy! My daddy!”—and disappeared into the backseat of the caseworker’s car.