It isn’t surprising that the ARC paper was looking for support for the Extreme Male Brain theory of autism. They tested transsexuals, female-to-male and male-to-female, “typical” males and females and people with Asperger syndrome. They used the Autism Quotient test. What they found was that male-to-female transexuals and typical males and females scored about the same. Female-to-male transexuals scored significantly higher than these groups in AQ, but significantly lower than people with Asperger syndrome. The concluding sentences in the abstract stated:
We speculate that these biological females, being masculinized in their autistic traits, may have had difficulties socializing with a female peer group and therefore found it easier to identify with a male peer group. This research illustrates how carefully selected groups in the population (e.g., congenital adrenal hyperplasia) can inform the extreme male brain (EMB) theory of autism.
I think this speculation is just that—speculation. I am not really comfortable with the speculation either. However, the idea of studying gender identity and autism stayed with me. So, I was very interested when I saw the abstract for the Noens study in the 2009 IMFAR abstracts.
Noens et al. took a different approach. They tested people for autism who were referred to the Amsterdam Gender Identity Clinic.
From April 2004 to December 2007, all children and adolescents referred to the Amsterdam Gender Identity Clinic were screened for ASD features.
Their preliminary results?
Preliminary results indicate that at least 6 % of the 233 referred children and adolescents has an ASD. This percentage remains almost the same for the referrals with a confirmed Gender Idenity Disorder (GID) or Gender Identity Disorder-Not Otherwise Specified (GID-NOS) diagnosis. The group of individuals with ASD and GID (seven adults included) is heterogeneous in various respects: sex (both male and female), GID classification (GID, GID -NOS, transvestic fetishism), ASD classification (AD, Asperger syndrome, PDD -NOS), age of onset of GID (before or after puberty), and developmental trajectory (cross-sex behavior temporary or persistent).
Pretty interesting, if you ask me. 6% of people referred to the clinic had an ASD. Unlike the results from the ARC group, there appears to be similarity in the male and female subgroups.
6%—about 6x the prevalence of autism in the general public. That is worth following up on.
There is, of course, another study one could consider: how many people with ASD ’s have GID ’s?
Note: I hope I have treated gender identity with respect. If I have made any disrepectful comments, I would welcome suggestions for correction.