level 1 autism does sometimes have a high IQ, although it can vary from person to person.
Most people with level 1 autism have an IQ of at least 85 or higher, but it can vary.
Many level 1 autistic people exhibit "twice exceptional" traits, which means that they possess profound cognitive strengths, like advanced logic, pattern recognition, or encyclopedic knowledge on specific topics, alongside of genuine neurodevelopmental challenges like social communication deficits or executive dysfunction.
90% of autism is caused by genetics.
Autism is also highly heritable, although autism is not caused by a single gene and instead autism is actually a complex, multifactorial condition that is drive by several biological and environmental factors.
However the vast majority of autism risk does come from a combination of variations in inherited genes from both parents as well as spontaneous or (de novo) genetic mutations, which occur during early development.
And hundreds of genes are also linked to autism, and each also slightly increase susceptibility to autism.
The remaining 10 percent of autism risk is attributed to prenatal and environmental influences.
These prenatal and environmental influences that cause autism include maternal health complications, exposure to certain chemicals such as air pollution or certain pesticides during pregnancy, extreme prematurity and even advanced age at the time of conception.
Autism rarely has a single cause and it's often the result of a complex interplay between a person's genetic makeup and environmental triggers during early brain development.
Specifically, children born to fathers over age 40 face a notably increased risk of developing autism.
Studies from various countries have found that these children are about 5.75 to 6 times more likely to be diagnosed with autism than those with fathers under 30.
Autism rates are also rising primarily due to better screening, broader diagnostic definitions, and increased public awareness, rather than a sudden spike in the condition itself.
Key factors driving these changes include:
Broader Definitions: The criteria for diagnosing Autism Spectrum Disorder (ASD) have widened.
In 1994, conditions like Asperger's were added, bringing milder traits into the spectrum.
Improved Screening & Awareness: Routine developmental screenings in early childhood—along with greater awareness by parents and educators—have drastically improved identification.
Better Inclusivity: Diagnosis rates for girls and previously underrepresented minority groups are catching up as clinicians better understand how autism presents differently across genders and ethnicities.
Diagnostic Substitution: Children who may have previously been diagnosed with another learning disability or intellectual delay are now receiving a more accurate autism diagnosis.