Men, it has been well said, think in herds; it will be seen that they go mad in herds, while they only recover their senses slowly, and one by one.
~Charles Mackay

People’s extraordinary sensitivity to the beliefs and behaviors of others, especially successful and socially visible others, contributes to the spread of useful skills and ideas and is critical to building and maintaining cultural knowledge. The benefits that follow from this sensitivity, however, come with the risk of being swept up in popular delusions. As Mackay noted, “We find that whole communities suddenly fix their minds upon one object, and go mad in its pursuit; that millions of people become simultaneously impressed with one delusion, and run after it, till their attention is caught by some new folly more captivating than the first.”

Susceptibility to popular delusions appears to be a human universal, although some people are more susceptible than others. These delusions can coalesce around just about anything the human mind can imagine, from get-rich-quick schemes to fear of demonic possession to blaming outgroups for moral decay. And though they are sometimes innocuous, they are also potentially dangerous. In Europe from 1500–1700, for example, tens of thousands of women and men were killed for being witches.

Debates and ideas about the number of sexes or genders and associated identities have all the makings of a popular delusion. A Google search for “gender identity” yields more than 800,000,000 entries; the same search under news yields more than 12,500,000 entries. Public discussion is clearly fixated on the topic, despite the indisputable evidence that there are only two sexes in complex organisms and that issues with gender identity have been historically uncommon.

A transgender person is someone whose natal sex (sex assigned at birth) does not match their gender identity (e.g., a natal female who identifies as a man). In some cases, a person’s gender identity may fall into a category other than “man” or “woman,” a state that is often labeled “non-binary.” There are in fact people with gender dysphoria (persistent and intense distress over one’s natal sex) and related concerns; that is not at issue.

Instead, the issue is the startling recent increase in the numbers of individuals who identify as transgender (or some related identity) and the risk of false positives, that is, individuals who for whatever reason believe they are transgender but are not. If the belief stayed in the individual’s mind and immediate social circles, there is no harm done. However, irreversible medical interventions are increasing as well, along with attendant risk of mistaken interventions that are later regretted.

Lisa Littman exposed this five years ago, writing that the current expression of gender dysphoria “is distinctively different than what is described in previous research … because of the distribution of cases occurring in friendship groups with multiple individuals identifying as transgender, the preponderance of adolescent (natal) females, the absence of childhood gender dysphoria, and the perceived suddenness of onset.” In other words, a large group of adolescent girls’ (and some adolescent boys’) understanding of their sexual identity has been influenced by their peer groups. These children do not show typical patterns (e.g., cross-sex play) associated with gender dysphoria and a transgender identity. The pushback against Littman’s argument was immediate and severe and continues to this day in the medical literature and more broadly.

It’s a good time to revisit this issue and to explore and try to explain the recent increase in the number of adolescent girls and young women who have a transgender or related identity. The argument is not that gender dysphoria and transgender identities are unreal, but that the almost obsessive fixation on transgender issues is increasing the risk of false positives (e.g., misattributing emotional distress to gender identity when the underlying cause is something else) among adolescents and young adults. I focus here on girls and women because of the changes in the demographics associated with gender dysphoria and gender identity issues. As Mackay illustrated, men are also prone to social contagion effects, but these occur more often with status-related beliefs, such as get-rich-quick schemes and collective violence. Adolescent girls and young women, in contrast, may be more attracted to inclusion in a socially supportive community, with benefits, such as increased social attention and popularity.

How common are transgender people?

Estimates of the number of people who identify as transgender or non-binary vary widely, depending on criteria for inclusion and the population being studied. Some of these estimates come from the percentage of the population who has sought, or is seeking, some form of medical intervention (e.g., surgery, hormone treatments). Other estimates are based on survey responses to questions about a transgender or ambivalent gender identity (e.g., non-binary).

Prevalence estimates for those who have received or are seeking a medical treatment are based on the number of people served by gender clinics relative to the size of the clinic’s catchment population. These studies indicate a low but increasing prevalence. In past eras, twice or three times as many natal males as females sought such treatment. One meta-analysis (a respected method for combining results across studies) published in 2015 indicated that one in every 14,705 individuals were transwomen (i.e., natal males who identified as women), and one in every 38,461 individuals were transmen (i.e., natal women who identified as men). A more recent study estimated that in 1976 about one in every 17,857 natal males and one in every 52,632 natal females sought hormone therapy as a treatment for gender identity and related concerns. By 1990, one in 11,905 natal males and one in 30,303 natal females sought similar treatments, indicating a modest increase from 1976 to 1990.

The trend has accelerated since then. Based on the National Inpatient Sample (US), Canner and colleagues found that from 2000 to 2014, the proportion of inpatients with gender-related diagnoses more than tripled, as did the proportion of individuals seeking a medical intervention (e.g., genital surgery). Leinung and Joseph found that the number of people seeking hormone therapy in upstate New York increased steadily from 1991 to 2016 and that the change was especially pronounced for natal females: “The percentage of individuals seeking transition to male gender was frequently 0% in the years up to 2002, but increased thereafter with the average increase in percentage seeking transition to male gender rising by 21% per decade.” The ratio of men to women seeking hormone therapy is now close to 1:1. Similarly, Aitken and colleagues found that the number of adolescents seeking treatment for gender dysphoria increased substantively after about 2006 and that the sex ratio flipped from more natal males (1.5 to two times more) before 2005 to more natal females after this (1.7 to 1.8 times more).

Studies based on the number of people seeking surgical or hormonal treatment underestimate the proportion of the population that identifies as transgender. A review of large national (US) surveys revealed that one in 256 people identified as transgender in 2016, which is about twice the number in 2007. The change across time was especially large for college students. In 2009, one in 665 students identified as transgender, as compared to one in 56 in 2016, a nearly 12-fold increase in seven years! A more recent review indicated that from 2017–2020, about one in 200 adults in the US identified as transgender, as did one in 71 adolescents. The figure below shows that among those who identify as transgender, the percentage of adolescents and young adults is larger than would be expected based on their share of the overall US population. As with individuals seeking medical treatments, the ratio of transwomen (natal men) and transmen (natal women) is approaching 1:1 (specifically, 1.07:1).

The proportion of adolescents and young adults identifying as transgender varies considerably across US states. In the state of New York, one in 33 adolescents identify as transgender as compared to one in 179 in Wyoming. Arkansas boasts the largest percentage of young adults identifying as transgender (one in 28) and, about 650 miles to the north, Iowa the lowest (one in 222). There are also reports of more localized spikes in the number of adolescents identifying as transgender or non-binary. One recent study found that nearly one in 10 high school students in a north-eastern school district identified as transgender or non-binary.

These wide variations and localized spikes are consistent with social influences on the likelihood of identifying as transgender (or a related identity). Some of these changes may be related to the laudable goal of removing the stigma associated with a transgender identity. However, the rush to destigmatize, support, and affirm those with gender dysphoria and gender identity issues, combined with social media, has created incentives to mimic these issues to gain support and affirmation. These motivations almost certainly increase false positives and promote harmful, unnecessary medical interventions.

Why are rates increasing among adolescent girls and young women?