Draped in a royal blue wool cape, my female-born autistic brother wears a homemade pin that reads, “I am a transgender male and I’m proud.” The 23-year-old points to it whenever he’s at restaurants, anticipating people making pronoun mistakes, which have been aggravating him for nearly two years.

For several years, he has been dressing like a boy, though his interpretation of what is “masculine” differs from most transgender males. For him, the color blue signifies masculinity more than attempting to “pass” as a man, and so he chooses to wear only monochromatic blue athletic clothing all the time.

He has been cutting his hair at a man’s barbershop for a decade, but he only came to identify as male roughly two years ago. He said the epiphany came to him after waking up from a nap, kind of like in Virginia Woolf’s Orlando, in which the male-born protagonist suddenly awakens a woman.

When he first announced his decision to identify as male, I assumed there weren’t many people out there who were both on the autism spectrum and dealing with gender identity disorder. But studies show that there is an increasing overlap between ASD (autism spectrum disorder) and GID (gender identity disorder) or gender dysphoria. According to a 2007 study, children and adolescents who meet the DSM-IV-TR criteria for GID have a much higher rate of also falling on the autism spectrum (7.8% vs. 1% of the general population).

Both ASD and GID are difficult for mental health professionals to concretely diagnose, as they rely on multiple behavioral and biological factors, and therefore estimates of people who have both autism and gender disorder are speculative.

According to a recent article, “Gender Dysphoria and Co-Occurring Autism Spectrum Disorders,” “There is no agreed-upon etiology for either ASD or GD, and all hypotheses are controversial. Biological factors (e.g. genetic predisposition, intrauterine hormones, and impact of environ-mental toxins), social factors (e.g. differential treatment of boys and girls, relationships with parents and peers), and psychological factors (e.g. cognitive issues complicating the formation of gender identity) have all been proposed with the understanding that there is likely a multifactorial etiology for both ASDs and GID.”

Particularly those who are transitioning from female to male have above average autistic traits, and more males than females are diagnosed with autism. Some researchers speculate that autistic traits are more aligned with “systemizing” than “empathizing,” which is more common in male brains. Simon Baron Cohen’s “extreme male brain” theory states that people on the autism spectrum display an extreme of the typical male brain cognition pattern. This theory does not address higher rates of male-to-female transgender identification among autistic people and has been criticized for its simplification of sex binaries.

One in 68 American children and 1% of the world’s population are on the autism spectrum, and numbers are on the rise. An estimation of 2 to 5% of the population is transgender.

Both autism and gender identity disorder develop during early childhood, but can be diagnosed later in life. Those on the autism spectrum tend to have difficulty with social interaction and communication, are often prone to repetitive behavior and have a different sense of self.

Perhaps because autistic people are less aware of their social environment, they come to have more fluid notions of gender identity. Aron Janssen, a child psychiatrist who specializes in gender identity counseling, told me, “In many ways, our gender roles are influenced by societal norms and expectations. For some people on the autism spectrum, they are less aware of these norms and expectations. As such, it is possible that some folks have less awareness of the expectations of what it 'means' to be a boy or a girl and can be somewhat more authentic in their expression of interests.“

Because gender is a social construction, and people on the autism spectrum have difficulty processing social cues, they are less influenced by the rigidity of gender binaries. Children on the autism spectrum are more likely to socialize with members of the opposite sex without feeling self-conscious.

“At this point, we can only postulate as to why there is an overlap between ASD and gender dysphoria. In part, I think there are some qualities of individuals with ASD (such as rigidity, intolerance of ambiguity and difficulty with theory of mind) that in some ways may actually open up one’s internal experience to the more diverse expressions of gender,” says Janssen.

People who identify as transgender and are also on the autism spectrum can be marginalized within the LGBT community. Though gender identity and sexual orientation are more fluid for those who are on the autism spectrum than those who are not, transgendered people with autism or Asperger’s syndrome still represent a minority within an already marginalized group of people. When my brother first started contributing to LGBT and transgender chat rooms on Facebook, he was often kicked out because neuro-typical strangers misinterpreted the intentions of his comments. Though his comments sometimes had nothing to do with transgender issues (one example being a detailed description of Disney character Rattigan Mars), being kicked out of these groups made him feel excluded and rejected in the one space he felt comfortable socializing—the Internet.

“Why are they kicking me out for no apparent reason?” he asked.

Those on the autism spectrum who want to get gender reassignment surgery must go through a rigorous psychiatric assessment and be persistently diagnosed with GID. Though the process for someone who has autism isn’t any different from someone who doesn’t, there is often an assumption that people on the autism spectrum lack the capacity to make these decisions for themselves. But gender identity disorders are complex and variegated for anyone, regardless of whether or not they have developmental disabilities.

“Gender identity is a core developmental process that begins to form as early as age 2-3. Even children with profound developmental delays can nevertheless be very clear about their gender,” says Janssen.

More than simply being clear about their gender identity, it is possible that people on the autism spectrum, less inhibited by social constructs, are able to conceptualize gender fluidity in a way that neuro-typical people are not.