Autism 101
Early Signs of Autism, by Developmental Stage
The short answer
Early signs of autism often involve social communication: limited response to a name, few gestures such as pointing or waving, little back-and-forth babbling, differences in eye contact, strong sensory reactions, and repetitive movement or play. Signs can appear before 12 months or become clearer around 18 to 24 months. Any single sign is not a diagnosis, but a pattern is a reason to request an evaluation.
Educational information, not medical advice. This guide is written to help you ask better questions. It does not diagnose, and it does not replace the judgment of your child's licensed clinicians.
How to use this page
This is not a screening tool and it cannot tell you whether your child is autistic. It is a plain-language map of what clinicians look for, organized by age, so you can describe what you are seeing accurately when you ask for help. The CDC's Learn the Signs. Act Early. program publishes the official milestone checklists and a free milestone tracker app, and those are the documents to bring to an appointment.
Infancy, roughly birth to 12 months
- Limited or inconsistent response to their name by around 9 to 12 months.
- Few back-and-forth exchanges: little babbling in response to you, few shared smiles, limited copying of your facial expressions.
- Few gestures by 12 months, such as pointing, waving, or reaching up to be picked up.
- Not following your point or your gaze to look at something you are showing them.
- Unusually strong or unusually flat reactions to sound, light, or being held.
Toddlerhood, roughly 12 to 36 months
This is the age at which most autism-specific screening happens, and when patterns typically become easier to describe.
- Limited spoken words by 16 to 18 months, or few two-word phrases by 24 months.
- Loss of words, gestures, or social skills the child previously used. This warrants a prompt conversation with your pediatrician.
- Little pretend play: lining up, sorting, spinning, or repeatedly examining parts of toys instead of feeding a doll or driving a car.
- Not bringing objects over to show you purely to share interest.
- Strong distress with transitions, new places, clothing textures, haircuts, or specific sounds.
- Repetitive movements such as hand flapping, toe walking, rocking, or spinning.
- Intense, narrow interests, or deep focus on letters, numbers, wheels, or fans.
Preschool, roughly 3 to 5 years
- Difficulty with the back-and-forth of peer play: joining in, taking turns, following a shared storyline.
- Speech that is present but scripted, echoed from shows, or highly literal.
- Very strong need for sameness in routine, route, food, or clothing, with big reactions to change.
- Sensory-driven behavior at school: covering ears, leaving loud rooms, seeking movement or pressure.
- Skills that look uneven: advanced reading or memory alongside significant difficulty with dressing, toileting, or unstructured time.
Autistic children who mask, meaning they suppress their reactions to fit in, are frequently identified later. A child who holds it together all day at school and melts down the moment they get home is a recognized pattern, not a discipline problem.
What to do if you see a pattern
- Write down what you see, with dates and specific examples. "Did not respond to her name 6 of 10 tries on Aug 3" is far more useful to a clinician than "seems distant."
- Ask your pediatrician directly for developmental and autism-specific screening at the next visit, and ask for the result in writing.
- In parallel, contact your state's early intervention program if your child is under three, or your public school district if your child is three or older. You can request an evaluation yourself, in writing, without a diagnosis and without a doctor's referral.
- Ask to be placed on the waitlist for a comprehensive developmental evaluation while the other steps proceed. Waitlists are commonly months long.
- Keep every report, screening result, and letter together in one place. You will be asked for them repeatedly.
Frequently asked questions
- At what age can autism be diagnosed?
- A reliable diagnosis can often be made by around age two, and some children are identified earlier. Many children are diagnosed considerably later, especially those who mask their differences or who speak fluently.
- My pediatrician said to wait and see. What now?
- You can request an early intervention or school evaluation yourself, in writing, without a referral. You can also request a second opinion. Waiting costs access to services that are easiest to get early.
- Does a delay in speech mean autism?
- No. Speech delay has many causes, including hearing differences and speech-specific conditions. A hearing test is a standard early step, and an evaluation is what sorts out the cause.
Sources
About the author
Rachell DumasLived experience
Co-founder, BASE
Rachell is a co-founder of BASE and a parent raising a child on the autism spectrum. She writes from lived experience coordinating therapy schedules, school communication, evaluations, and benefits paperwork across a large care team.
This guide has not been reviewed by an outside clinician. It is written from lived caregiving experience and cites the primary sources listed above so you can verify every detail yourself.