But almost nothing is known about the mental health of a new and growing generation of transgender Americans -- prepubescent children who are living openly as transgender with the support of their families. How do those children fare in an environment of openness and family support? When their gender identity is affirmed, are they happy?
New University of Washington research suggests the answer is yes. Published Feb. 26 in Pediatrics, the study is believed to be the first to look at the mental health of transgender children who have "socially transitioned," changing their preferred pronouns and typically, their names, clothing and hairstyles.
The research found that the 73 children, age 3 to 12, had rates of depression and anxiety no higher than two control groups -- their own siblings and a group of age- and gender-matched children. And their rates of depression and anxiety were significantly lower than those of gender-nonconforming children in previous studies.
The findings, said lead author Kristina Olson, challenge long-held assumptions that mental health problems in transgender children are inevitable, or even that being transgender is itself a type of mental disorder.
"The thinking has always been that kids who are not acting gender-stereotypically are basically destined to have mental health problems," said Olson, a UW assistant professor of psychology. "In our study, that's not the case."
Co-author Katie McLaughlin, a UW assistant professor of psychology, called the findings "incredibly promising."
"They suggest that mental health problems are not inevitable in this group, and that family support might buffer these children from the onset of mental health problems so commonly observed in transgender people," she said.
The study involved having parents complete two short surveys under the National Institutes of Health's Patient-Reported Outcome Measurement Information System. The surveys asked parents whether their children had experienced symptoms of depression or anxiety during the past week -- for example, feeling sad or being worried when going to bed.
The research found that the transgender children's levels of depression averaged a score of 50.1, almost the same as the national norm of 50. Their anxiety rates were 54.2, only slightly higher than the national norm.
The higher anxiety rates aren't exactly surprising, Olson said. Though transgender children are becoming increasingly visible in the mainstream media -- the most well-known, 15-year-old Jazz Jennings, is the subject of a new documentary series -- their reality remains little understood even within the medical community.
Transgender people were long classified under the umbrella of "gender identity disorder" by the widely used Diagnostic and Statistical Manual of Mental Disorders (DSM). The term was replaced with "gender dysphoria" in 2013, after considerable debate and lobbying from advocates to remove the word "disorder" from its name.
"It is hard to be transgender in 2016 in the United States," Olson said. "If peers know that a child is transgender, they often tease that child. If peers do not know, the transgender child has to worry about being found out. It's not surprising that transgender children would have some more anxiety, given the state of the world for transgender children right now."
The researchers acknowledge that the positive mental health among study participants might be explained by factors other than just parental support. Parents could be biased in their reporting, for example, wanting their kids to appear healthier than they are. Or the children themselves might have personality traits, such as confidence, that correlate to a healthy emotional state. Future studies will investigate these possibilities.
The study is part of the TransYouth Project that Olson leads. The initiative is the first large-scale, longitudinal study of transgender children in the U.S. It currently involves more than 150 transgender children and families from about 25 states, and Olson is recruiting additional participants. The project's initial study, published in 2015, found that transgender children's gender identities were as deeply rooted as those of their non-trans peers.
The researchers next plan to look at how factors outside of the family, such as treatment by peers, might predict mental health in transgender children, and whether the age of transition makes a difference.
"It will be important to follow these children over time, particularly during the transition to adolescence, to understand patterns of mental health and positive adjustment across development for transgender youth who are supported by their families," McLaughlin said.
Olson said while there is still a tremendous amount to be learned about transgender children, the study's findings suggest it's possible for them to live happier lives than previous generations of transgender people.
"I think they're proof that you can be a young transgender kid today and be happy and healthy and doing just as well as any other kid," she said. "It's some good news, finally, which I don't think there's much of in what we hear about transgender kids."