What are the earliest signs of autism in babies and toddlers?

Early signs of autism can appear in the first year of life. Parents should watch for limited eye contact or social smiling by six months, not responding to their name consistently by 12 months, lack of pointing or gesturing by 12 months, absent or delayed babbling, and loss of any previously acquired language or social skills at any age. The 18-month and 24-month pediatric well-child visits include standard autism screening, but if you notice these signs before then, request an evaluation rather than waiting for the next scheduled appointment.

What is the difference between autism symptoms in girls versus boys?

Autism is diagnosed about four times more often in boys than girls, but research increasingly shows that girls are underdiagnosed rather than less affected. Girls with autism often develop stronger social masking skills, learning to imitate social behaviors without fully understanding them, which can make their challenges less visible to teachers and clinicians. Girls may appear to have friendships but struggle deeply with the unspoken demands of those relationships. If you have concerns about your daughter and have been told she does not "seem autistic," seeking a second opinion from a specialist with experience diagnosing autism in girls is worthwhile.

How does ABA therapy help children with autism, and at what age should it start?

Applied Behavior Analysis (ABA) therapy is the most extensively researched intervention for autism. It uses individualized, structured teaching methods to build communication, social, self-care, and behavioral skills, while also addressing behaviors that interfere with learning or safety. ABA can benefit children across the age range, but the evidence is strongest for early intervention, ideally beginning between ages two and five, when the brain is most adaptable. The earlier a child begins receiving appropriate support, the greater the potential for meaningful developmental gains. Many families begin ABA therapy shortly after an initial diagnosis, even if a formal evaluation is still in process.

Autism Symptoms in Children: What Parents Should Know

Introduction

Watching your child grow and develop is one of the most profound experiences a parent can have. But when something feels different, when your child isn't reaching certain milestones, struggles with communication, or responds to the world in unexpected ways, it can leave families with a lot of questions and very few clear answers.

Autism Spectrum Disorder (ASD) is a neurodevelopmental condition that affects how a person communicates, learns, and interacts with others. According to the CDC, about 1 in 31 children in the United States is diagnosed with autism, a number that has grown significantly over the past two decades, in part due to improved awareness and screening. Understanding what autism looks like in children, especially in the earliest years, is one of the most important things a parent, educator, or caregiver can do.

This guide breaks down the core symptoms of autism in children, what early signs look like in toddlers and young children, and why getting support early can make a meaningful difference in a child's life.

Understanding Autism Spectrum Disorder

Autism is called a "spectrum" disorder for a reason: it looks different in every child. Some children with ASD are highly verbal and academically strong but struggle intensely with social relationships. Others may be nonverbal or have significant delays in multiple developmental areas. Still others fall somewhere in between, with a unique blend of strengths and challenges.

What connects these children is a shared set of core differences in social communication, behavior, and sensory processing, though the degree and combination of these differences vary widely from one individual to the next.

ASD is not caused by parenting. It is not caused by vaccines. It is a complex neurological condition with roots in genetics and brain development, and it is lifelong. What changes with the right support, however, is a child's ability to navigate the world, build relationships, and reach their potential.

Core Autism Symptoms in Children

Autism symptoms generally fall into two broad categories: differences in social communication and interaction, and restricted or repetitive behaviors and interests. Here is what these look like in practice.

Social Communication and Interaction

Children with autism often experience the social world differently from their neurotypical peers. This is not about being shy or introverted. It reflects genuine differences in how the brain processes and responds to social information.

Many children on the spectrum show reduced or inconsistent eye contact from an early age. A child may not look up when their name is called, or they may look at faces in ways that feel slightly off, scanning rather than connecting. Parents frequently describe feeling like their child looks "through" them rather than "at" them.

Language development is another common area of concern. Some children with autism develop speech on a typical timeline but use it in unusual ways, repeating phrases from TV shows or books (a pattern called echolalia), struggling to maintain a back-and-forth conversation, or speaking in a very literal manner that misses sarcasm, humor, or social nuance. Others experience significant speech delays or may not develop spoken language at all without intervention.

Nonverbal communication differences are also common. Children with ASD may rarely share an interest in something ("Look, a dog!"), gesture to communicate needs, or use facial expressions in the ways their peers do. The combination of wanting to share experiences and not knowing how to do so is one of the more heartbreaking and often overlooked early signs.

Friendships often prove difficult. A child with autism may genuinely want connection but not know how to initiate or sustain it. They may prefer parallel play over interactive play, gravitate toward younger children or adults rather than same-age peers, or seem puzzled by the unspoken rules of social interaction that come naturally to others.

Restricted and Repetitive Behaviors

The second core category of autism symptoms involves patterns of behavior, thought, and interest that are noticeably rigid, intense, or repetitive.

Repetitive motor movements, rocking, hand-flapping, spinning, and finger-flicking are common and serve as self-regulatory tools for many children with autism. These are sometimes called "stimming" (self-stimulatory behavior) and are a normal part of autism, not something to shame or suppress.

Intense, narrow interests are another hallmark. A child might develop an extraordinary depth of knowledge about trains, weather systems, a specific TV franchise, or any number of other topics, and have difficulty shifting focus to anything else. These interests are not a problem in themselves. With the right support, they often become a tremendous strength.

Insistence on sameness and difficulty with transitions are very common. Many children with autism rely on predictable routines as a way of managing a world that often feels overwhelming. A change in the morning schedule, a different route to school, or a substitute teacher can trigger significant distress, not because the child is "difficult," but because predictability is genuinely regulating for them.

Sensory sensitivities round out this picture. Children with autism frequently experience sensory input more intensely than their peers. Certain sounds may be physically painful. Clothing tags, food textures, or the feel of grass under bare feet can provoke strong reactions. Bright lights, crowded spaces, and strong smells can be genuinely overwhelming. Understanding a child's sensory profile is essential to supporting them effectively.

Autism Symptoms in Young Children: What to Watch For

Early identification is one of the most important factors in a child's long-term outcomes, which is why pediatricians screen for autism at the 18-month and 24-month well-child visits. But parents are often the first to notice that something feels different, sometimes before any formal screening occurs.

Here is what autism may look like in infants, toddlers, and preschoolers.

In infants and toddlers (6 to 18 months): By around six months, most babies are smiling socially and making eye contact with familiar caregivers. By nine months, they are typically sharing smiles, sounds, and facial expressions in back-and-forth exchanges. By 12 months, most babies are pointing, waving, and responding to their name consistently.

Children who will later be diagnosed with autism often show reduced social engagement during this window. They may not smile back as reliably, may not follow a pointed finger to look at something, and may not respond to their name with the same consistency as peers. Some parents describe this period as a gradual fading. Their baby seemed engaged early on, then seemed to withdraw. Others note that their child was always a bit different in these early months.

In toddlers (18 to 36 months): This is the period when autism becomes more visible in most children. The language and social milestones that are typically developing in this window are often delayed, absent, or qualitatively different in children with ASD.

A child who was using a few words may stop using them. A child may develop a script of phrases but not use language to truly communicate. A child may become intensely focused on lining up toys, spinning wheels, or watching the same video segment on loop. Tantrums may be more frequent and more difficult to resolve, particularly around transitions or sensory triggers.

One thing we hear often from families we work with: "I knew something was different, but I didn't know what it was." That instinct deserves to be taken seriously.

In preschoolers (3 to 5 years): By this stage, differences in social play become more apparent as children enter group settings. A child with autism may play alongside peers without actually engaging with them. Pretend play may be absent or very scripted. Language may be present but used in unusual ways. Meltdowns and rigidity around routine may become more pronounced as the demands of the environment increase.

It is worth noting that autism in girls is often missed or diagnosed later than in boys, in part because girls frequently develop stronger "masking" skills, learning to imitate social behaviors without fully understanding them. If you are concerned about your daughter, do not let a dismissal of your concerns be the final word.

The Case for Early Intervention

Early diagnosis does not just give a name to what you are observing. It opens the door to evidence-based support that can genuinely change the trajectory of a child's development.

The brain is at its most plastic, most adaptable, in the first several years of life. When a child receives intensive, individualized intervention during this window, the gains can be remarkable. Research consistently shows that children who receive early behavioral intervention make significantly greater gains in communication, adaptive behavior, and social skills than those who begin intervention later.

Applied Behavior Analysis (ABA) therapy is the most thoroughly researched behavioral intervention for children with autism. It is the only intervention recognized as evidence-based by both the American Academy of Pediatrics and the U.S. Surgeon General. ABA is not a one-size-fits-all approach. At its best, it is individualized, play-based, and built around understanding what motivates each child.

We have seen this play out directly in our work with families. A three-year-old who arrived at our clinic with no functional communication and significant self-injurious behaviors began requesting preferred items within the first month of therapy. By eighteen months into his program, he was using full sentences, navigating peer play with support, and showing dramatically reduced distress behaviors. Early, intensive intervention made that possible.

That is not an outlier. It is what the research predicts, and what we see regularly.

Is Your Child Showing Early Signs? Let's Talk.

Early support makes the biggest difference, and you don't have to figure out the next step alone. At Career Based Solutions, our early intervention ABA programs are built around each child's unique needs, whether that's in your home, our clinic, or their school.

Connect with us by calling 540-931-2853 or sending an email to info@careerbasedsolutions.com. Families across Virginia trust us to help their children thrive, and we'd love to do the same for yours.

How ABA Therapy Supports Children with Autism

ABA therapy works by breaking skills down into manageable steps and teaching them systematically using positive reinforcement. It addresses a wide range of goals depending on what each child needs, including communication skills, daily living skills, social and play skills, emotional regulation, and reducing behaviors that interfere with learning or safety.

At Career Based Solutions, services are tailored to meet families where they are. For some children, in-home ABA therapy is the right fit, working on skills in the environment where the child actually lives, with family members actively involved in the process. For others, a clinic setting provides more structured learning opportunities and peer interaction. For school-age children, school-based ABA therapy ensures that the skills being built translate directly into the academic setting.

Parent training is a core component of effective ABA therapy, not an add-on. Parents and caregivers are a child's most constant teachers. When families are equipped with the strategies their child's program uses, the gains made in therapy carry over into every part of a child's life.

For families in Virginia navigating the school year or looking for intensive support during breaks, a summer ABA therapy program can provide continuity of services during a period when many children regress without structured intervention.

When to Seek an Evaluation

If you are reading this and recognizing some of what is described in your child, an evaluation is the right next step. You do not need a referral to request a developmental evaluation, though your child's pediatrician can be a helpful starting point.

Some things to look for as you consider next steps:

Your child is not meeting language milestones, no babbling by 12 months, no single words by 16 months, no two-word phrases by 24 months.
Your child has lost skills they previously had, and any regression in language, social behavior, or communication at any age warrants prompt evaluation.
Your child's play is very repetitive or rigid, and they become highly distressed by changes to routine.
Your child does not seem interested in other children or engages with them in consistently unusual ways.
Your child has significant sensory sensitivities that interfere with daily life.
Trust your instincts. Parents know their children. If something feels different, it is worth investigating, not because there is something wrong with your child, but because getting the right support early can matter enormously.

Conclusion

Autism is not a tragedy. It is a different way of being in the world, one that comes with real challenges, yes, but also with genuine strengths, gifts, and a perspective that enriches the communities around it. What children with autism need is not to be fixed, but to be understood, supported, and given the tools to navigate a world that was not always designed with them in mind.

The symptoms described in this guide, from social communication differences to repetitive behaviors to sensory sensitivities, are the starting point of that understanding. Recognizing them early, taking them seriously, and connecting with evidence-based support like ABA therapy gives children the best possible foundation.

You do not have to navigate this alone. The right team, the right approach, and the right timing can make a real difference.

Ready to Take the Next Step?

Career Based Solutions is here to help. We provide individualized ABA therapy and parent support services to families across Virginia, including Garrisonville, King George, and Thornburg. Whether you are just starting to ask questions or ready to begin services, our team is available to talk through your options and help you find the right path forward.

Contact us today to schedule a consultation. Your child's progress starts here.

Frequently Asked Questions

What are the earliest signs of autism in babies and toddlers?
Early signs of autism can appear in the first year of life. Parents should watch for limited eye contact or social smiling by six months, not responding to their name consistently by 12 months, lack of pointing or gesturing by 12 months, absent or delayed babbling, and loss of any previously acquired language or social skills at any age. The 18-month and 24-month pediatric well-child visits include standard autism screening, but if you notice these signs before then, request an evaluation rather than waiting for the next scheduled appointment.
What is the difference between autism symptoms in girls versus boys?
Autism is diagnosed about four times more often in boys than girls, but research increasingly shows that girls are underdiagnosed rather than less affected. Girls with autism often develop stronger social masking skills, learning to imitate social behaviors without fully understanding them, which can make their challenges less visible to teachers and clinicians. Girls may appear to have friendships but struggle deeply with the unspoken demands of those relationships. If you have concerns about your daughter and have been told she does not "seem autistic," seeking a second opinion from a specialist with experience diagnosing autism in girls is worthwhile.
How does ABA therapy help children with autism, and at what age should it start?
Applied Behavior Analysis (ABA) therapy is the most extensively researched intervention for autism. It uses individualized, structured teaching methods to build communication, social, self-care, and behavioral skills, while also addressing behaviors that interfere with learning or safety. ABA can benefit children across the age range, but the evidence is strongest for early intervention, ideally beginning between ages two and five, when the brain is most adaptable. The earlier a child begins receiving appropriate support, the greater the potential for meaningful developmental gains. Many families begin ABA therapy shortly after an initial diagnosis, even if a formal evaluation is still in process.