This article is a collaboration between The New Yorker and ProPublica.

In September, 2016, Jenn Thompson and her boyfriend, Robbie Ray, discovered that she was pregnant. They had met just over a month earlier, through the dating app Tinder, and quickly became inseparable. Robbie would stay at Jenn’s place several nights a week, and on the weekends they tailgated at football games. The pregnancy was unplanned, but both had recently turned thirty and were ready to start a family. When they went in for an ultrasound appointment, a technician pointed out two tiny circles on the screen: twins. They bought a baby Doppler and Robbie would hold the monitor on Jenn’s stomach so they could listen to the two hearts beating in tandem.

They got married five months later, at the Lutheran church Jenn attended. Robbie moved into her house, in Columbia, South Carolina, across the street from her parents in a tightly packed development of modest, newish homes tucked behind a shopping complex. They converted the second bedroom into a nursery. Jenn found the crib she slept in as an infant and gave it a fresh coat of paint. The babies arrived more than a week early, by C-section—a boy first, and then a girl.

Over Memorial Day weekend, when the twins were three weeks old, half a dozen excited family members came to Jenn and Robbie’s home and took turns cradling the twins. The girl seemed particularly fussy. At times, she cried so hard that she seemed unable to catch her breath. Robbie later called it a “scary cry.” But the couple figured she was just colicky. Then, the following Tuesday, as Jenn was feeding her, she noticed swelling and bruising on the baby’s right leg. She told me that she called Robbie, who was at work, driving a truck for a uniform-supply company, to tell him that something was wrong. Jenn’s mother came over and told her to take the baby to the pediatrician. The same doctor had examined the twins just a week earlier and found them to be in good health. This time, he told Jenn to take the infant to the emergency room at nearby Palmetto Health Children’s Hospital immediately.

An X-ray revealed that the baby’s leg was broken in two places, both near the ankle. The new parents said that nothing remarkable, no accidents, had occurred during the previous few days. Robbie wondered aloud if he had unintentionally hurt her while putting lotion on her legs or changing a diaper. Called in by the E.R. staff, Dr. Susan Lamb, a pediatrician specializing in child abuse, noted a pattern of bruising “consistent with an adult hand gripping the calf” and a fracture caused by “extreme” force, according to a South Carolina Department of Social Services report.

The hospital staff then examined the other twin. X-rays revealed a fracture in his left leg. A doctor found bruising on his back. The next day, as Jenn and Robbie sat with the twins at the hospital, social workers and security staff converged on the room. A sheriff’s deputy handed the couple an emergency order to take the twins into state custody.

Some among the medical staff and social workers involved in the case thought that Jenn reacted strangely to the discovery of her children’s injuries. She didn’t show emotion or seem bothered. Her affect was “flat,” according to the D.S.S. report. The hospital’s abuse specialist concluded the baby girl’s fractures were “diagnostic of physical abuse” and that the bruises were “inflicted.” D.S.S. concluded the boy’s injuries were also the result of abuse. A factor in this determination was that Robbie and Jenn did not have “a plausible explanation” for the injuries. “We had no idea,” Robbie told me later.

To find an explanation, the Rays said, they searched the Internet and eventually discovered a group called Fractured Families. The Web site was filled with stories of parents who were accused of abuse—falsely, it said—after their children were found to have bone injuries. Jenn told me that she was struck by how similar their experiences were to her own. Jenn made contact with several of the mothers in Fractured Families. They told her that there was a doctor in Boston who might be able to help her.

Michael Holick has a tenth-floor office at Boston University, where he is a professor at the medical school. His windows offer a view of the tree-canopied medical-school campus below. A makeshift system of plastic bags and buckets is rigged to collect the rain water that often leaks in. Gray tape binds the air duct, and the tiled floor is stained. Two lab coats hang in the corner and a stethoscope rests on a desk next to photographs of Holick’s wife and two adult children. Holick has worked in this space since he first arrived on campus, thirty years ago.

In the past seven years, Holick said, he has consulted or testified as an expert witness in more than three hundred child-abuse cases throughout the U.S., as well as the United Kingdom, New Zealand, Australia, Germany, and Canada. In almost every case, he has made the same finding: instead of blaming any injuries on abuse, he has diagnosed the child with a rare genetic disorder, hypermobile Ehlers-Danlos syndrome, a condition that affects the connective tissues of the skin, bones, and joints. A handful of studies on adults have linked EDS to bone fragility, and Holick argues that children with the disorder have weaker bones, which can fracture from normal handling. So far, his theory is not supported by the scientific literature, but Holick is convinced that “thousands, if not tens of thousands,” of parents worldwide have been falsely accused of fracturing their children’s bones. “It’s just terrible,” he told me. “I feel so sorry for these parents.”

In all the cases he has worked on, Holick has never concluded that a child was being abused. On the rare occasions when he didn’t diagnose EDS, he attributed the bone fractures to rickets or Vitamin D deficiency. Many geneticists and bone specialists find it troubling that he diagnoses EDS in nearly a hundred per cent of the cases he examines. According to the National Institutes of Health, EDS affects, at the most, 0.02 per cent of people worldwide. The rate at which Holick diagnoses the disorder “doesn’t fall into the mathematical probability of chance,” Brad Tinkle, a clinical geneticist at Peyton Manning Children’s Hospital, in Indianapolis, said. Holick retorts that his clients don’t come to him by chance; parents contact him after doing their own research and realizing that they or their children have symptoms of EDS. He adds that he hasn’t seen a single actual abuser pretending to have EDS and contacting him in search of a “get out of jail free” card.

Holick regularly diagnoses children with EDS without seeing them in person. “I already know on the phone they have EDS,” he said, adding that he questions the parents about potential symptoms. “I almost don’t have to ask. I know the answer.”

Dr. Michael Holick is one of the most prominent and sought-after expert witnesses for the defense in child-abuse cases; his career has also been dogged by controversy. Photograph by M. Scott Brauer

In 2008, a father named Kenneth Grad was indicted for felony assault and endangering children after X-rays of his infant son, taken at Akron Children’s Hospital, revealed twenty-six fractures of the fingers, arms, legs, ribs, and skull, according to court documents. Holick examined the baby's mother, Laura Grad, and diagnosed classic signs of hypermobility. Without examining the baby, Holick submitted an affidavit attributing the fractures to EDS. However, a test by the family’s pediatrician found that the baby did not have hypermobility. Grad was convicted in December, 2014, and a month later was sentenced to twenty-four years in prison. “The mom has EDS and so too likely the child,” Holick wrote in an e-mail, adding that, if the injuries weren’t due to bone fragility, “the amount of trauma to cause that number of fractures … would likely have resulted in the infant’s death.”