Boys and men are significantly more likely to be diagnosed with autism than girls and women, with a typical ratio of around four males for every one female diagnosed. However, several other factors also increase the risk, including genetics and parental age.
Autism prevalence is reported to be highest among non-Hispanic white children, lower in Hispanic and African American/black children, and highly variable in Asian/Pacific Islanders. More comorbid intellectual disability and delays in expressive language have been observed among Hispanic and African American children.
Around 90% of autism cases are attributed to genetic factors, meaning autism is highly heritable, with many different genes contributing, rather than a single cause, often interacting with environmental influences during early brain development, though specific environmental factors don't cause it but can increase risk. Twin studies show strong genetic links, with concordance rates between 60-90% in identical twins, and research points to complex interactions of many genes and prenatal/perinatal factors.
However, scientists found a strong genetic component from the father that contributed to an autism diagnosis in siblings. The research does not conclude the father will carry an autism gene in every case, but it found autistic siblings tend to share their father's genome at a near double rate compared to the mother's.
Researchers are not sure what causes autism, but they believe genetic and environmental factors play a role. Risk factors can include having older parents or a sibling with ASD, genetic or chromosomal conditions like Down syndrome or fragile X syndrome, and very low birth weight.
There's no known way to prevent autism spectrum disorder. But many studies have been done to see if taking folic acid and other vitamins before and during pregnancy can lower the risk of having a baby with autism spectrum disorder. A review of studies on what are known as prenatal vitamins shows no clear answer.
Research tells us that autism tends to run in families, and a meta-analysis of 7 twin studies claim that 60 to 90% of the risk of autism comes from your genome. If you have a child with autism, you are more likely to have another autistic child.
A comprehensive analysis involving over 5.7 million children revealed that children of fathers in their 40s and 50s show a significantly higher prevalence of autism. Specifically, offspring of fathers over 50 are approximately 66% more likely to develop autism than those with fathers under 30.
The "6-second rule" for autism is a communication strategy where a speaker pauses for about six seconds after asking a question or giving information, giving the autistic person extra time to process it without feeling rushed, which helps reduce anxiety and allows for a more thoughtful response, reducing frustration for both parties. Instead of repeating or rephrasing, which can be confusing, you wait, and if needed, repeat the exact same words after the pause.
For instance, research involving nearly 5 million birth records in California from 1992 to 2000 found that children with fathers over 40 were about 6 times more likely to have autism compared to those with fathers under 30. Similarly, children born to mothers aged 35 or older showed approximately a 40% increased risk.
While the exact reasons are not yet clear, changes in how the disorder is defined, increases in screening, and more awareness certainly contribute to this increase. If you have any concerns about your child's development, speak to a healthcare professional about diagnostic tests.
Autism in young children
Understanding the 6 stages of an autism meltdown can help parents, caregivers, and educators respond with empathy and support.
In the largest study of its kind, researchers have shown that the risk of autism increases for firstborn children and children of older parents.
Donald Triplett, autism's 'Case 1,' dies at 89. Triplett gained media attention for his autism later in life, and he became the face of the effort to research the lives of older adults with autism.
Countries with the Highest Reported Autism Rates
Children with autism may exhibit rigidity, inflexibility and certain types of repetitive behavior such as: Insistence on following a specific routine. Having difficulty accepting changes in the schedule. A strong preoccupation with a particular interest.
Chinning is a form of repetitive self-stimulatory behavior (stimming) that you may notice in children or adults with autism. It involves pressing, rubbing, or holding the chin against objects, surfaces, or even hands to gain sensory input or comfort.
There's no single "hardest" age for autism; challenges shift across developmental stages, with preschool (2-5) often tough due to noticeable differences in social/language skills, elementary (6-10) marked by growing academic/social demands, and adolescence (11-17) frequently being overwhelming due to complex social pressures, puberty, and identity formation, say Bluebell ABA Therapy and Blossom ABA Therapy. While early childhood (ages 3-6) sees initial progress for many, this often stalls around age six, a critical turning point where increased support is crucial, according to research, notes The Transmitter.
Experts haven't found a single cause of autism. It's likely a combination of genetics and certain things related to pregnancy, labor and delivery. You might see these things described as “environmental factors” or “prenatal events.” These factors all interact to lead to the brain differences we see in autism.
Clinicians who encountered autism in the 1950s and 1960s called it by many names. Among them were Kanner's syndrome (named after Leo Kanner), early infantile autism, hyperkinetic disease, and Heller's disease (based on 1908 description by Austrian educator Theodor Heller), also known as dementia infantilis.
Autism can be inherited from either parent, with both maternal and paternal genes playing significant roles. Studies show that siblings of children with autism tend to share more DNA from their fathers, suggesting a stronger paternal genetic influence.
The first is the broadened definition of Autism Spectrum Disorder, which means that more people are meeting this definition now than previously. Second, there have been many widely successful public health programs that increased screening at wellness visits for children ages 18–24 months to look for signs of autism.
What NOT to Say to Someone with Autism
While autism is typically not diagnosed before the age of 2 (and often much later), it can sometimes be detected earlier. A 2022 study found that a routine second-trimester ultrasound could detect early signs of autism during pregnancy,18 including anomalies in the heart, head, and kidneys.