If you’re noticing something different about your son’s development and wondering whether it could be autism, you’re not alone. About 1 in 31 children in the U.S. are now identified with autism spectrum disorder, making it one of the most common developmental conditions. No article can diagnose your child, but understanding the specific signs at each age, what the evaluation process looks like, and what to expect can help you take the next step with confidence.
Signs to Watch for by Age
Autism shows up differently depending on how old your child is. In the first year of life, you might notice your son doesn’t use gestures like waving goodbye by 12 months, or doesn’t play simple interactive games like pat-a-cake. He may not respond to his name consistently, even though his hearing is fine.
By 18 months, a key milestone is pointing. Most toddlers point at things to share their interest with you: a dog walking by, an airplane in the sky. A child on the autism spectrum often doesn’t do this. By 24 months, you’d typically expect a child to notice when someone else is hurt or upset. If your son seems unaware of other people’s emotions, or doesn’t look at your face to gauge your reaction to something, that’s worth paying attention to.
Other signs that can appear across these ages include limited or no eye contact, not babbling or using words on a typical timeline, and not engaging in back-and-forth social exchanges like smiling when you smile at him. Some children also show an unusual fascination with specific objects, like spinning wheels on a toy car rather than playing with the car itself, or lining toys up in precise rows instead of using them in imaginative play.
Repetitive Behaviors and Sensory Differences
Autism involves more than social differences. A diagnosis requires at least two types of restricted or repetitive behavior patterns. These can look very different from one child to another.
- Repetitive movements or speech: Hand flapping, rocking, spinning, or repeating words and phrases (sometimes called echolalia). Some children repeat lines from TV shows in place of original speech.
- Rigid routines: Extreme distress over small changes, like taking a different route to daycare or using a different cup. Your son might insist on eating the same food every day or follow greeting rituals in a very specific order.
- Intense, narrow interests: A deep fixation on a specific topic or object that goes well beyond typical childhood enthusiasm. Think memorizing every detail about trains, fans, or numbers to a degree that crowds out other activities.
- Sensory sensitivities: Overreacting to certain sounds, textures, or lights, or the opposite: seeming not to notice pain or temperature. Some children excessively smell or touch objects, or become visually fascinated with lights and movement.
Not every child will show all of these, and the intensity varies widely. A child who lines up toys occasionally is doing something perfectly normal. A child who lines up toys for hours, becomes inconsolable when the line is disrupted, and shows social differences alongside that behavior is presenting a different picture.
When Children Lose Skills They Already Had
Some parents notice their son developing normally and then losing abilities he previously had. This is called regression, and it typically happens between the second and third year of life, with an average onset around 20 months. Language loss is the most commonly reported type: a child who was saying words or short phrases stops using them. But regression can also involve social skills like eye contact, interest in other people, and imitative games like peek-a-boo. A smaller number of children lose motor skills or basic self-care abilities like self-feeding.
If your son was hitting milestones and then stopped, or if he seems to be losing skills he once had, that pattern is particularly important to bring to your pediatrician’s attention.
Why Autism Can Look Different in Some Children
The classic image of autism, a child who doesn’t speak and avoids all social contact, represents only one end of the spectrum. Many children with autism are verbal, affectionate, and socially interested but struggle with the nuances of social interaction: reading facial expressions, understanding unspoken rules, or adjusting their behavior for different social settings.
There’s also growing recognition that autism can present differently based on gender. Girls with autism tend to camouflage their traits more than boys, forcing themselves to maintain eye contact, mimic appropriate facial expressions, or suppress unusual behaviors to fit in. Research shows females score significantly higher on measures of camouflaging than males. This means girls are more likely to fly under the radar, but boys can camouflage too, especially those with fewer obvious behavioral differences. If your son seems to hold it together at school but falls apart at home, that contrast is worth noting.
What a Formal Evaluation Looks Like
Only a trained specialist can determine whether your child meets the criteria for autism. The evaluation is typically done by a developmental pediatrician, child psychologist, speech-language pathologist, or occupational therapist, and sometimes by a team that includes several of these professionals. During the evaluation, the specialist will observe your child directly, use structured assessments to look at social communication and behavior, and ask you detailed questions about your son’s development and daily life. You may also be asked to fill out questionnaires about his behavior at home.
A diagnosis requires persistent differences in all three areas of social communication (back-and-forth social interaction, nonverbal communication like gestures and eye contact, and the ability to build and maintain relationships) along with at least two types of the repetitive or restricted behaviors described above. These patterns need to show up across multiple settings, not just at home or just at school.
One thing to prepare for: wait times can be long. A recent study found that the median wait for a children’s autism assessment was 525 days, or roughly a year and a half. Children with more complex medical or developmental histories waited even longer, averaging about 100 weeks compared to 68 weeks for less complex cases. If your pediatrician flags concerns, getting on a waiting list early matters. Some families pursue evaluations through multiple pathways (private specialists, hospital-based clinics, university programs) to shorten the wait.
What Autism Levels Mean
If your son does receive a diagnosis, it will include a support level ranging from Level 1 to Level 3. These levels describe how much support he needs in daily life, not how “severe” his autism is in some fixed sense.
Level 1 means “requiring support.” Children at this level can speak in full sentences and manage many daily tasks but struggle with social flexibility, making friends, and switching between activities. Level 2, “requiring substantial support,” involves more noticeable social communication differences and more rigid or repetitive behaviors that interfere with daily functioning. Level 3, “requiring very substantial support,” describes children with minimal verbal communication and significant difficulty with change or new situations.
These levels can shift over time with development and intervention. A child diagnosed at Level 2 as a toddler may function at Level 1 after years of speech therapy and social skills support.
What to Do With Your Concerns Right Now
Start by writing down specific behaviors you’ve noticed, with examples and approximate dates. “He doesn’t point at things” is useful. “He stopped saying ‘mama’ around 19 months” is even more useful. This kind of concrete detail helps professionals assess your son more accurately.
Your pediatrician can perform a developmental screening, which is a brief check for red flags. The American Academy of Pediatrics recommends autism-specific screening at 18 and 24 months, but you can request one at any visit if you have concerns. A screening isn’t a diagnosis. It tells you whether a full evaluation is warranted.
If your son is under three, you can also contact your state’s early intervention program directly, without a referral, and request a free developmental evaluation. Early intervention services are available regardless of income, and you don’t need a formal autism diagnosis to qualify. The earlier support begins, the more impact it tends to have on language, social skills, and adaptive behavior.