Behind Florida's decision to block clinical services for transgender adolescents is a talking point — repeated by the state's governor and top medical authorities — that most cases of gender incongruence fade over time.

The Florida Board of Medicine voted Nov. 4 to approve a rule that barred physicians from performing surgical procedures on minors to alter "primary or secondary sexual characteristics" and from prescribing them medication to suppress puberty and hormones. The rule included an exception for patients who were already receiving those treatments. 

Two days later, Florida's Republican governor, Ron DeSantis, said gender-affirming care is "an example of ideology overtaking the practice of medicine," touting that he worked with the board to take a stand against it. 

"Over 80% of the dysphoria amongst teenagers resolves itself by the time they become older," DeSantis said during a Nov. 6 campaign event. "So why are you mutilating their body parts?"

Earlier in the year, the Florida Department of Health used the statistic as it advised against medical transitioning for minors. The department's April memo said, "80% of those seeking clinical care will lose their desire to identify with the non-birth sex." 

Dr. Hector Vila, a Tampa anesthesiologist and member of the governor-appointed board, said he supported the rule because a "significant percentage" of transgender children will return to their assigned sex.

PolitiFact consulted with experts and data to determine whether gender incongruence will "resolve itself" for a large cohort of teenagers.

The experts we interviewed said Florida mischaracterized a statistic linked to an academic review from 2016. What's more, the doctor whose work is cited as the statistic's source has said the data he consulted is not "optimal" and can lead to "wrong inferences."

The rule will take effect shortly after the public comment period ends Dec. 5.

The 80% figure comes from a 2016 paper published in the "International Review of Psychiatry." 

Dutch health psychologist Thomas Steensma and Italian psychologist Jiska Ristori examined past studies on gender dysphoria, which describes the distress people may experience because of a discrepancy between their gender identity and the sex assigned to them at birth.

Not all transgender people experience or are diagnosed with gender dysphoria. Gender dysphoria diagnoses focus on gender identity-related psychological distress, not gender identity itself.

The researchers wanted to know whether people who experienced gender dysphoria as children still had it later in life. They looked at the outcomes for children involved with 10 studies conducted from 1968 to 2012 in the U.S., Canada and the Netherlands. 

Their review of the studies said they showed that gender dysphoric feelings went away for 85% of children "around or after puberty" — while acknowledging several limitations. 

"There may be a number of arguments to nuance this high percentage of desistence," the review read. "The lower persistence rates in the earlier studies, compared to the more recent studies after 2000, may be the result of the inclusion of less extreme cases in the earlier studies than in later studies."

In other contexts, the term "desistence" can refer to an apparent end of gender variance and a return to an identity that aligns with the sex assigned at birth. In the paper, the researchers meant the lifting of dysphoric feelings.

Other experts mentioned concerns with the methodology of studies cited in the paper. 

Dr. Kristin Dayton, a pediatric endocrinologist, said the studies had a small share of children assigned female at birth — and are thus not representative samples of the population. Eight of the 10 studies examined only children assigned male at birth.   

At least six of the studies were conducted before the American Psychiatric Association developed a formal diagnosis for gender dysphoria in children. Some of the 10 studies did not include children who were referred to the studies by medical professionals. 

A 1987 study, for instance, used advertisements to recruit children. Only 30% of the children examined had "frequently" stated a desire to be a girl. Experts said most of the children in that study wouldn't have met the current criteria for gender dysphoria. 

The diagnostic criteria for the condition include a "marked incongruence" between one's experienced gender and assigned sex at birth lasting at least six months and a "strong desire to be of the other gender or an insistence that one is the other gender."  

Florida's Department of Health and Board of Medicine misrepresented the review's conclusion by stating 80% of children will "lose the desire" to identify with a sex not assigned at birth.

The 80% figure in the review did not reference children's gender identities; it centered on the persistence and desistence of gender dysphoria in adulthood. Steensma later wrote that "using the term desistence in this way does not imply anything about the identity of the desisters." 

Although the review noted that the studies found a "strong association" between gender dysphoria in childhood and a "lesbian, gay or bisexual outcome," it did not say what percentage of people studied stopped identifying as transgender.

"The 80% statistic, used by the Florida Department of Health and the state's leadership, is categorically false," Dr. Meredithe McNamara, an assistant professor of pediatrics at the Yale School of Medicine, told PolitiFact. "After a close read of the scholarship cited by the state, the state's conclusion simply cannot be drawn in good faith."

Steensma, who did not respond to PolitiFact's requests for an interview, has responded to criticism from colleagues about how his research is used to discourage social and medical affirmation for gender diverse adolescents. 

"We want to stress that we do not consider the methodology used in our studies as optimal … or that the terminology used in our communications is always ideal," Steensma wrote in 2018. "As shown, it may lead to confusion and wrong inferences." 

McNamara also said that Florida's reliance on a 2016 paper is a "glaring problem," because the state neglected to consider about six years of new research.

A study published in July, for instance, sought to develop an estimate of transgender children who later stop identifying with a gender incongruent with their assigned sex.

It evaluated 300 transgender children over five years. To participate in the study, children must have already begun social transitioning, which often involves changing names, haircuts and pronouns. 

Researchers from Princeton University's TransYouth Project followed up with participants in-person and online. At the end of the five years, 94% of participants still identified as transgender.