There’s a particular kind of quiet that settles in when you notice something feels different about how your child is developing. Maybe it’s that they don’t look up when you call their name. Maybe it’s that they’ve stopped using words they had a few months ago. Maybe it’s an instinct you can’t quite name — just a sense that something is worth paying attention to.

That quiet is not paranoia. It’s the beginning of understanding.

This article is for parents who are in that moment — somewhere between noticing and knowing. We’ll walk through what the research tells us about the early signs of autism spectrum disorder (ASD) in toddlers and young children, organized by age in the way your daily life is organized: not by clinical domain, but by where your child actually is right now.

If you’re already past this stage — if a diagnosis has arrived and you’re now figuring out what comes next — you can explore how Luna Family Autism supports families after diagnosis. Most families start care within days of their first call.

What the research tells us about early autism signs

According to CDC’s Autism and Developmental Disabilities Monitoring (ADDM) Network — the most comprehensive U.S. surveillance system for autism — approximately 1 in 31 children aged 8 years is identified with ASD as of 2022. That’s a significant increase from earlier estimates (it was 1 in 36 just two years prior), driven largely by improved identification across racial and ethnic groups and expanding diagnostic criteria.

ASD is more than three times as common in boys as in girls, though recent research suggests girls may be underdiagnosed due to differences in how autism presents across genders.

The reason early identification matters so much comes down to a straightforward clinical fact: the brain is more malleable in the early years. When children receive support — whether through early behavioral intervention, speech therapy, or family-led approaches — during the period when the brain is most responsive to change, outcomes are substantially better across communication, behavior, and social development.

This isn’t about urgency or alarm. It’s about giving your child the best possible start with the support that’s available — and the American Academy of Pediatrics recommends that all children be screened for autism at 18 and 24 months precisely because these early years are when support is most effective.

Early signs by age: what to look for — and what’s typically developing alongside it

The CDC describes two core domains where autism signs appear: social communication and interaction, and restricted or repetitive behaviors. Across both, early signs emerge gradually — and it’s the pattern across multiple areas, not any single behavior, that warrants attention.

Around 12 months

What typically develops: Most 12-month-olds babble in varied tones, respond to their name most of the time, wave goodbye, and point or reach toward things they want. They’re beginning to show interest in other people’s faces and expressions.

Red flags to notice:

• Not responding to their name when called
• No babbling, or babbling that sounds monotone rather than conversational
• No gestures — no waving, no reaching up to be held
• Limited or inconsistent eye contact in social moments
• Not showing interest in other people’s reactions

The researchers at the UCSD Autism Center of Excellence note that vocal atypicalities in the first year — vocalizations that sound more like monotone humming than conversational babbling — can be among the earliest observable differences in children who are later diagnosed with ASD.

Around 18 months

What typically develops: Most 18-month-olds have 5–20 words, understand simple instructions (“come here,” “give me that”), point to show others something interesting, and engage in simple back-and-forth play.

Red flags to notice:

• No words, or fewer than expected (noting: some children are late talkers without autism — see the section below)
• Not pointing to show you something of interest
• Not following your pointing gesture when you show them something
• Limited joint attention — looking at an object, then back at your face to share the experience
• Unusual sensory reactions: strong aversion to textures, sounds, or foods that seem disproportionate to the trigger

Joint attention — the shared act of looking at something together and checking in with each other’s faces — is one of the most reliable early indicators. It typically emerges around 9 months and should be well established by 18 months, according to the UNM Center for Disability’s autism portal.

Around 24 months

What typically develops: Most 2-year-olds have 50+ words and are combining two words (“more juice,” “daddy go”). They engage in simple pretend play, notice when others are upset, and show increasing interest in other children.

Red flags to notice:

• Fewer than 50 words, or not yet combining two words
• No pretend play — not using objects symbolically (using a banana as a phone, feeding a stuffed animal)
• Not noticing when others are hurt or upset
• Increased rigidity — strong distress over minor changes in routine or environment
• Repetitive behaviors becoming more prominent: lining objects up, spinning wheels, hand flapping

Around 36 months

What typically develops: Most 3-year-olds can hold simple conversations, engage in cooperative play with other children, and follow multi-step instructions. They’re showing increasing awareness of social rules and other people’s perspectives.

Red flags to notice:

• Not joining other children in play, even when given the opportunity
• Echolalia — repeating words or phrases they’ve heard (from you, from TV) without clear meaning or function
• Very narrow, intensely held interests
• Significant distress with minor changes in routine
• Repetitive motor behaviors that are persistent and not serving an obvious function

Is it autism — or is my child a late talker?

This is the question most parents in this moment are actually asking. And it deserves a direct answer.

A speech delay alone is not a red flag for autism. Some children are late talkers — they develop language more slowly than their peers, but their social communication is intact: they make good eye contact, they point, they share experiences, they respond to their name, they engage in back-and-forth play. These children often catch up without intervention, though speech therapy can be helpful.

What distinguishes a late talker from a child showing early signs of autism is the presence of differences in social communication — not just speech.

Signs that suggest more than a speech delay:

• Speech delay accompanied by reduced eye contact or limited interest in faces
• Not pointing or showing objects to share interest (even without words, this gesture is present in most typically developing 12-month-olds)
• Not responding to name consistently
• Limited back-and-forth engagement — the conversational rhythm of interaction, even non-verbal
• Unusual attachment to objects, strong preference for sameness, or repetitive sensory behaviors

A developmental pediatrician, speech-language pathologist, or psychologist can make this distinction through a formal evaluation. If you’re uncertain, the conversation with your child’s pediatrician is worth having — and having specifically, with your observations rather than a general “I’m worried about their speech.”

One warning sign that often gets missed: regression

Regression — when a child loses skills they previously had — is a distinct and critical red flag that sometimes gets mistaken for a temporary setback or a phase.

According to Autism Speaks, some children with ASD gain new skills and meet developmental milestones until around 18 to 24 months of age — and then stop gaining new skills, or lose skills they once had. This pattern of regression often affects language and social skills simultaneously: a child who was using words stops. A child who was waving goodbye no longer does.

This is not a phase. Any loss of previously held speech, babbling, gestures, or social skills is a signal that warrants prompt attention from your child’s pediatrician — regardless of whether other red flags are present.

If you’ve noticed regression in your child, document what they could do and when it changed. Specific observations are more useful to an evaluating clinician than general impressions.

If your child has recently received an autism diagnosis, or you’re waiting on an evaluation, you can learn what to do in the weeks and months that follow. Most families who call Luna are in exactly that in-between place — and that’s the right time to ask questions.

What to do if you notice these signs

Talk to your pediatrician — and be specific

General concerns (“I’m worried about his development”) are harder for pediatricians to act on than specific observations (“He stopped waving at 15 months,” “She doesn’t look up when I call her name”). Come to the appointment with notes: what you’ve noticed, when it started, and any changes from earlier behavior.

Ask your pediatrician to administer a formal autism screening tool at the 18- and 24-month visits. The AAP recommends this as standard practice at these visits — but not all families receive it unless they ask.

What M-CHAT-R screening looks like

The M-CHAT-R — Modified Checklist for Autism in Toddlers, Revised — is a 20-question screener designed for toddlers between 16 and 30 months. It’s completed by parents (typically during or before the well-child visit) and asks about specific behaviors your child does or doesn’t do.

The M-CHAT-R doesn’t diagnose autism. A positive screen means your child should be evaluated further — typically by a developmental pediatrician, psychologist, or multidisciplinary team. The evaluation process involves structured observation, parent interview, and standardized assessment tools.

After a diagnosis: what comes next

If your child is diagnosed with ASD, the path forward typically involves connecting with a developmental team (speech, OT, behavioral support), exploring therapy options, and navigating insurance and access. It can feel overwhelming — and most families describe the post-diagnosis weeks as some of the hardest, even after the relief of finally having answers.

This is where early intervention programs and ABA therapy enter the picture. Research on parent-implemented interventions consistently shows that when families are trained as active participants in their child’s behavioral support, outcomes are strong across communication, behavior, and social skills — even at lower direct therapy hours. A 2023 meta-analysis in the Journal of Autism and Developmental Disorders found an average effect size of g=0.553 for parent-implemented interventions — a moderately strong, meaningful result that held across diverse family situations.

Early support resources in Texas and Illinois

If your child is under 3 years old, there are state-funded early intervention programs specifically designed to support children with developmental differences — including children diagnosed with ASD and children who are in the evaluation process.

In Texas: The Early Childhood Intervention (ECI) program through Texas Health and Human Services provides developmental services for children ages 0–3 with qualifying diagnoses, including autism spectrum disorder. ECI is available in all Texas counties. Families can be referred by their pediatrician or self-refer — and services are free for families who meet eligibility requirements.

In Illinois: The Early Intervention (EI) Program is a statewide initiative for children under age 3 with developmental delays, administered through the Illinois Department of Human Services. Services are provided through Child and Family Connections (CFC) offices located throughout the state.

Both programs provide services under the federal Individuals with Disabilities Education Act (IDEA) Part C, which means evaluations are free and services are provided in the natural environment — typically the home.

These programs are for children ages 0–3. For children over 3 who have received a diagnosis, ABA therapy — including Luna’s virtual, family-led model — is typically the next step in the support pathway.

You noticed something. That matters.

The most important thing about early identification is that it starts with a parent who is paying attention. Not a specialist. Not a screening tool. A parent who knows their child and trusts what they’re seeing.

If you’re in that moment — watching carefully, carrying a quiet concern — your instincts are worth following. Talking to your pediatrician costs nothing. A referral for an evaluation gives you information, not a verdict.

And when — or if — a diagnosis arrives, there is a clear path forward. Families who get connected to appropriate support early, and who are trained as active participants in their child’s care, consistently see meaningful progress in communication, behavior, and connection.

You don’t have to have it all figured out before taking the next step. When you’re ready to explore what virtual, family-led ABA therapy looks like — and whether it’s covered by your insurance — Luna Family Autism’s team is here to answer those questions without pressure.

ABA therapy covered by Medicaid is available for qualifying families in Texas and Illinois. Most families pay $0 out of pocket. And most start within days of their first call — not months.

You can also explore Luna’s autism family education resources to understand how family-led support works before making any decisions.

Your child needs you to notice. You already did.