In the early 1970s, a general practitioner named M. P. Carter, who lived and worked mostly in the east of England, passed away. Later, when his wife went through the doctor’s personal effects, she found in his desk a list of names of twins with autism. Carter had been putting this list together since 1967, when he placed notices in several medical journals, asking “any doctor knowing of such a twin pair [to] please contact” him. Carter was active in Britain’s National Society for Autistic Children as its East Anglia organizer, and had been in touch with Bernard Rimland in the United States. The two men had been discussing some sort of joint study on autistic twins, but Carter had died before getting around to it.
Carter’s wife, recognizing that the short list of names was probably important, sought to get it into the hands of someone who could make use of it. That was how the names came to be given to a London professor of psychiatry named Michael Rutter.
Rutter, then in his early forties, was already the superstar of British child psychiatry and the first person in Britain named to a professorship in that discipline. Destined to be knighted by the queen later in his career, Rutter was recognized for his exacting intellect and for the rare and blunt clarity of his academic writing. Autism was but one of his interests, in which, as a thinker and researcher, he played a leading role throughout five decades, beginning in the 1960s.
In 1973, when Rutter first saw Carter’s list of twins, he saw the possibilities in it immediately. Other researchers had written about twins and autism, but only minimally, with only a few cases mentioned here or there and always with sparse data. But with a sufficient number of cases, Rutter thought he might be able to answer two intriguing questions at the same time: How frequently was autism shared between twins? And was the rate the same for identical and fraternal twins? Numbers like that had the potential to say a great deal about the role of genetics in autism. If analysis showed that autism was shared between identical twins at a higher rate than expected, that could answer the question of whether genes helped determine who had autism and who did not.
THE QUESTION HAD been taboo for several decades, a result of the lingering scientific scandal of genetic arguments used by the Nazis to justify the murder of people with mental disabilities. For many years after World War II, seeking a link between a person’s DNA signature and signs of mental illness or intellectual disability was not an endeavor that appealed to many researchers. Particularly in American psychiatry, nothing was more politically incorrect than the suggestion that there was any genetic dimension to the mind’s functioning. Feeding the taboo was the presence in America of many European-born psychiatrists who had escaped the Holocaust or who had family who had died in it. On this point, passion trumped the spirit of inquiry. When Danish psychiatrist Eric Stromgren visited the United States in 1948, he found it depressing that even “the possibility of genetic contributions” was something he was not permitted to broach with colleagues there. “Genetics had become a dirty word,” he recounted.
Besides, the mother-blaming theory, which still dominated, obviated all need for exploring the condition’s genetic or biomedical side. Taken together with the distaste for gene research, very little true scientific study of the biomedical aspect of autism was undertaken for years. But once he had the list of twins in his hands, Michael Rutter was ready to take on the taboo.
WHEN HE STARTED putting together the outlines of a study, Rutter settled on a target population: all sets of British twins—identical and fraternal—where at least one of the siblings appeared to be affected by autistic traits. That had been the organizing principle of Dr. Carter’s list, whose dozen or so names gave Rutter a good starting point. Now, as Carter had once done, Rutter reached out across the medical profession to contact pediatric centers, social service agencies, and mental hospitals with the aim of tracking down any pairs of twins Carter might have missed. Rutter received remarkable cooperation—a testament to his reputation, probably. Large envelopes of documents began arriving by mail, packed with the children’s full, original records.
These records all claimed autism diagnoses for at least one of the twins in each set, but Rutter wanted certainty that the diagnosis was valid. For him, that meant getting independent confirmation in each and every case. Every family on his growing list would have to be visited in person so that the children could be evaluated face-to-face. But the dozens of names on his list came from children scattered over hundreds of miles in the United Kingdom. He could not get to all these children himself; his duties at the Institute of Psychiatry demanded all of his time as it was. So he brought in an outsider.
Susan Folstein, who grew up in Missouri, was one of the five women admitted to Cornell Medical School in the class of 1970, when that was the ceiling for female enrollment. When she told a professor she hoped to become a professor herself someday, he counseled her to go “become an expert in something.” By chance, this same man had studied at the Maudsley and knew Michael Rutter. He put the two of them in touch.
Thus, in the summer of 1974, Folstein found herself in the far north of England, sloshing through a soggy field toward a small encampment of mobile homes, where she spotted a mother bending down to help a naked toddler urinate in the mud. The woman’s hair was waist-length and loose, the same orange-red as the child’s. There was no phone service out there, or electricity or running water. Still, the woman appeared not at all surprised to have an American suddenly showing up at her trailer. Some weeks earlier, a letter had arrived, and the woman, who could not read, had walked it into town to have the doctor who looked after her kids read it to her. It was from Folstein, explaining her research interest in the woman’s twin boys.
The two women took a seat inside the mobile home, surrounded by shelves of beautifully cut glass. More children joined them—lots of them. Folstein spent quite some time observing the twins, while asking their mother questions and explaining more about the purpose of the study. She also took care to inform the mother of some of what was known about autism. Over tea, the mother took all this in and then commented, “Huh! I guess there’s a reason for reading, after all.”
For most of 1974 and into the late spring of 1975, Folstein was on the road roughly two days out of every week, working through Rutter’s list of twins, crisscrossing the United Kingdom, taking tea with every social class. Autism was in all these places. That red-maned mother belonged to a social tribe referred to, usually unkindly, as “gypsies.” Folstein met other tribes, spending an afternoon in the midst of glorious gardens at the country mansion of a celebrity actress married to a famous musician, who were the parents of twins. On yet another day, she dined in the home of a retired general, grandfather to the children she’d come to see, eating bad food from silver plates. A good number of the children on the list were already institutionalized. Folstein found the grounds and the architecture of the mental hospitals picturesque but their interiors dark and dire.
In the course of these months, Folstein became the expert she aspired to be. She mastered the observation and reporting of autistic behaviors, using criteria set by Rutter. It was Rutter, though, who took command of her detailed reports to make the final determination of whether there were true autistic traits at play in these children. Working with Folstein, he eliminated cases where there might have been illness suffered, such as rubella, or physical trauma before or during birth—because those incidents could account for some of the observed behaviors. He wanted only those cases where the possibility of inheritance remained an open question, where both children were of the same sex, and where there were clear grounds for diagnosing autism in at least one of the pair.
Once Folstein’s travels were complete, her long journey yielded just twenty-one sets of same-sex twins who fit the study’s parameters of autism in at least one twin per set. This was not a surprisingly small number, given the relative rarity of twins in general, let alone of autism as defined by the study’s rather tight criteria. In any case, it would be the numerical relationships within this group that excited the autism world when Rutter and Folstein made their findings public in July 1976, at a conference in St. Gallen, Switzerland.
With Rutter looking on from the audience, Folstein took the stage and spelled out the numbers. Twenty-one sets of twins, she reported, had made the cut. Eleven sets of identical twins and ten sets of fraternal twins, with autism in one or both children in every pair. She and Rutter were virtually certain, she told the room, that they had not missed a single pair in their sweep of Britain. That number twenty-one, she reminded everyone, covered sets of twins where at least one twin had signs of autism—a small number, yes, but one that reflected the small odds of twin births crossing paths with autism in the first place.
Then Folstein revealed the crucial finding: all four pairings where both of the kids had autism were identical twin sets. At the same time, among the fraternal twins, whose DNA was no more closely matched than any ordinary brother and sister, autism never showed up in both kids.
It was stark, even in a sample set so small, and the conclusion was crystal-clear: genetic inheritance mattered in autism. As Folstein pointed out, the known odds of two kids in one family having autism were as low as 1 in 50. But with the identical twins described in the study, the odds soared to 1 in 3. That could be no coincidence. Genetics had to be in play.
That day was a turning point in the framing of the origins of autism. Over the next twenty-five years, the genetics of the condition would become an intensively researched area of investigation. Despite early hopes that the “autism gene,” or genes, would be found, no instant answers resulted. But each year, new pieces of the puzzle were consistently uncovered, coinciding with the full mapping of the human genome early in the twenty-first century. Eventually, genetic research tools were developed that were far more precise than were available to investigators when Susan Folstein took to the roads of Britain in 1974, leading to even deeper autism genome research.
The twin study was also one of the few UK-based studies of that period that did not center on the house on Florence Road, but that was only because twins with autism were few and far between. As the 1970s turned into the 1980s, researchers would continue paying visits to the children of Florence Road, as the questions they wanted to ask about autism became ever more sophisticated, and the answers ever more revealing.
This was especially true when, in the early 1980s, a young man with a briefcase stepped through the front door. He had two dolls inside the briefcase, and an idea for an experiment that would inform and intrigue anyone who had ever wondered what constituted the essence of autism.