JANETTE MILLER wasn’t exactly surprised when her daughter came out as transgender five years ago. A feminist who rarely wears make-up or dresses, she brought Rachel up to disregard gender stereotypes (these are not their real names). As a child Rachel enjoyed rough-and-tumble play; as a teenager, she dated a girl. What shocked Ms Miller was her daughter’s declaration that she wished to make her body more masculine by taking testosterone and having a mastectomy. “She had never once said, ‘I feel like a boy’,” says Ms Miller. “She loved being a girl.”

After Ms Miller started to research what a medical transition entailed, she told Rachel that “it was fine for her to identify however she wanted”, but she would not permit her to take testosterone, some of the effects of which are irreversible, or have “top surgery” until she was 18. They fought for months. Rachel says it felt “almost like a life-or-death situation.”

Typically, adolescents first show symptoms of gender dysphoria, the clinical term for the distress caused by the feeling that one’s body does not match one’s gender, in childhood. But in the past decade clinics in Western countries have reported that a growing number of teenagers have started experiencing gender dysphoria during or after puberty. And whereas these young adults used to be predominantly male, now they are more likely to be female. In 2009, 41% of the adolescents referred to Britain’s Gender Identity Development Service were female; in 2017, 69% were.

Lisa Littman, an assistant professor of behavioural and social sciences at Brown University, was curious about what was causing these changes. She had come across reports from parents on online forums describing a new pattern of behaviour: adolescents without a history of childhood gender dysphoria were announcing they were transgender after a period of immersing themselves in niche websites or after similar announcements from friends. Her study suggests that these children may be grappling with what she calls “rapid-onset gender dysphoria”.

For the study, Dr Littman recruited 256 parents of children whose symptoms of gender dysphoria suddenly appeared for the first time in adolescence. These parents—Ms Miller among them—took part anonymously in an online, 90-question survey. Dr Littman’s findings suggest that a process of “social and peer contagion” may play a role. According to the parents surveyed, 87% of children came out as transgender after spending more time online, after “cluster outbreaks” of gender dysphoria in friend groups, or both. (In a third of the friendship groups, half or more of the individuals came out as transgender; by contrast, just 0.7% of Americans aged between 18 and 24 are transgender.) Most children who came out became more popular as a result. Rachel, Ms Miller’s daughter, says that when she told her friends, all of whom she had met online, they congratulated her: “It was, like, welcome home.”

Dr Littman thinks that some adolescents may embrace the idea that they are transgender as a way of coping with symptoms of a different, underlying issue. Almost two-thirds of the children had one or more diagnoses of a psychiatric or developmental disorder preceding the onset of gender dysphoria; nearly half had self-harmed or experienced some trauma. This is consistent with other studies of gender dysphoria when it sets in during puberty. Some people distract themselves from emotional pain by drinking, taking drugs, cutting or starving themselves. Dr Littman suggests that, for some, gender dysphoria may also be in this category.

The study has attracted heavy criticism. Some is reasonable. Though it is a solid first attempt to describe a recently observed phenomenon, it is qualitative rather than quantitative, and relies solely on interviews with parents, not children. Dr Littman posted links to her survey on three websites where parents and clinicians had described the abrupt appearance of adolescent gender dysphoria: 4thWaveNow, Transgender Trend and youthtranscriticalprofessionals. Referring to these sites as “anti-trans”, Diane Ehrensaft, the director of mental health at a gender clinic in San Francisco, has written that “this would be like recruiting from Klan or alt-right sites to demonstrate that blacks really are an inferior race”. Dr Littman replies that 88% of the parents in her study said transgender people deserve the same rights as others, which is in line with national opinion. Similar methodology is frequently used in social research, particularly into children.

The reaction to publication of the study has gone beyond what might be expected in a regular academic dispute. Brown removed from its website a press release advertising her research, noting that PLOS ONE, the journal in which the study was published, was seeking “further expert assessment”. In a later statement, the university said: “There is an added obligation for vigilance in research design and analysis any time there are implications for the health of the communities at the centre of research and study.” Parents and academics have in turn attacked Brown for caving to pressure from trans activists.

Squashing research risks injuring the health of an unknown number of troubled adolescent girls. Rachel, now 21, believes she latched on to a trans identity as a way of coping with on-off depression and being sexually abused as a child. After receiving therapy, her gender dysphoria disappeared. Had her mother affirmed her gender identity as a 16-year-old, as several gender therapists urged, Rachel would have embarked on a medical transition that she turned out not to want after all.