Gender ratio in a clinical population sample, age of diagnosis and duration of assessment in children and adults with autism spectrum disorder.

Rutherford et al. (2016) looked at every new referral to one autism clinic in the UK. They noted each person’s sex, age when first referred, and how long the full assessment took.

The sample mixed children and adults. The team simply asked: are girls sent later than boys, and once sent, do they wait longer for answers?

Girls arrived at the clinic older than boys. Once the file was opened, boys and girls moved through the same steps in the same number of days.

In short, the delay happens before referral, not during testing.

May et al. (2018) saw the same late-girl pattern in all Australian Medicare claims. The national data extend the single-clinic finding to a whole country.

Gu et al. (2023) dug into electronic health records and found the wait is driven by anxiety or mood issues that hide ASD traits in girls. Their work gives a reason for the delay spotted by Marion.

Laposa et al. (2017) seems to disagree: among toddlers already accepted into early-intervention, boys and girls were the same age. The clash disappears when you see that this sample was very young; referral bias shows up later, once social demands increase.

If you screen intake forms and see a school-age girl with social worries plus anxiety, move ASD higher on your rule-out list. Ask about subtle play differences, not just stereotypic behaviors. Early probes can shave years off her wait.