When it comes to Autism Spectrum Disorder (ASD), there has long been a common assumption: males are more likely than females to be diagnosed. In fact, the diagnosis rate for boys is more than four times higher than for girls. However, a groundbreaking new study from the University of California, San Diego School of Medicine challenges that narrative—at least in early childhood. Published in Nature Human Behavior on May 26, 2025, this research reveals no significant clinical differences in autism traits between toddler boys and girls at the time of first diagnosis. This discovery could have a profound impact on how autism is detected and treated in the critical early years of life.
This article explores the study’s findings in depth, examines what it means for early intervention strategies like home ABA therapy in North Carolina, and offers insights for parents and caregivers navigating the journey of autism support.
The Study: A Comprehensive Look at Autism Traits in Toddlers
Between 2002 and 2022, researchers at the UC San Diego Autism Center of Excellence assessed over 2,500 toddlers ranging in age from 12 to 48 months. This diverse group included:
- 1,500 toddlers with autism
- 600 typically-developing toddlers
- 475 developmentally delayed toddlers
The researchers used 19 comprehensive metrics to evaluate the children, including:
- Language development
- Social and motor skills
- Cognitive functioning
- Repetitive behaviors (a core autism trait)
- Daily living skills, such as dressing or feeding oneself
- Social attention using eye-tracking technology
All assessments were conducted by licensed clinical psychologists at a single site, ensuring consistency and reliability.
Key Findings: No Early Gender Differences in Autism Traits
The study’s most compelling discovery was that male and female toddlers with autism did not show significant differences in clinical traits—except for one minor metric.
- Daily living skills (as reported by parents) showed slightly higher scores for females, suggesting that girls may develop some practical abilities earlier than boys.
Beyond this, researchers found no differences across 18 other categories, including those related to communication, social skills, cognitive development, or repetitive behaviors.
To further validate their results, the research team grouped the toddlers into low, medium, and high-ability subtypes within the autism spectrum. Even across these scientifically robust categories, no major differences between boys and girls emerged.
They also tracked developmental trajectories from 12 to 48 months, once again finding no gender-based variations.
“There is no consensus in the field about whether females are more or less impacted than males, and that is probably because there haven’t been really large-scale studies at the earliest ages. Based on previous small studies, we had anticipated there would be some sex differences. So we were a little bit surprised to find nothing at all.”
– Karen Pierce, Ph.D., Professor of Neurosciences and Director of the Autism Center of Excellence at UC San Diego School of Medicine
What About Typically Developing Children?
Interestingly, the study did find notable gender differences among typically developing toddlers. Girls outperformed boys on more than half of the developmental tests, particularly those involving:
- Social interaction
- Language development
- Daily living and adaptive skills
This aligns with existing literature showing that neurotypical girls tend to mature faster in communication and social areas during early childhood.
“Typically developing females are accelerated in their development relative to males,” said Pierce. “This is consistent with the literature.”
Rethinking Early Diagnosis of Autism
One of the critical takeaways from the study is that previous assumptions about gender-based differences in autism traits may have been flawed. According to Dr. Pierce, this discrepancy could stem from:
- Small sample sizes
- Sampling bias
- Limited measures
- Methodological shortcomings
Alternatively, she proposes that gender differences may not exist at the point of early diagnosis, but instead emerge later, influenced by socialization, cultural expectations, or biological changes that unfold over time.
To better understand this, Dr. Pierce recommends a long-term, large-scale study that tracks children from toddlerhood through school age and beyond.
Implications for Early Intervention: Focusing on Individual Needs
One of the most profound implications of this study is the potential shift in how we understand and treat autism in young children.
Rather than looking at autism through a gender-based lens, researchers suggest categorizing children into developmental subtypes based on their strengths and challenges.
This nuanced approach allows for personalized treatment plans, such as:
- In-home ABA therapy in North Carolina
- School-based ABA therapy services North Carolina
- Customized language development programs
- Parent coaching and family involvement in therapy
Such early intervention efforts have been shown to be highly effective, especially when initiated before age three.
“If you can improve a toddler’s language and communication at the youngest ages possible, then they’re going to get their needs met better, and they’re going to be able to contribute to society more effectively,” said Pierce. “It’s really about having every child reach their full potential.”
Why This Matters: Empowering Parents and Providers
The findings from this large-scale study can help parents, caregivers, educators, and healthcare providers make more informed decisions when it comes to early autism intervention.
For families seeking home ABA therapy in North Carolina, it reinforces the importance of early screening, regardless of gender, and encourages focusing on the child’s unique developmental profile rather than assumptions based on sex.
Programs offering in-home ABA therapy services North Carolina or ABA home therapy North Carolina can benefit from these insights by:
- Customizing therapy goals to match developmental subtypes
- Using objective assessment tools rather than gender norms
- Engaging parents and siblings in holistic care models
- Tracking individual progress instead of relying on generalized expectations
Moreover, educators working within school-based ABA therapy services North Carolina can use this research to foster gender-neutral intervention strategies and provide equal opportunities for both boys and girls to thrive.
The Road Ahead: Continuing the Conversation
As we move forward, studies like this encourage a more inclusive and evidence-based understanding of autism spectrum disorder. They also emphasize the need for:
- Greater public awareness
- Training for clinicians and educators
- Access to equitable early intervention services
- Family support systems that adapt to individual child needs
By prioritizing early diagnosis and personalized care, we can help children with autism—regardless of gender—build the foundational skills they need to live fulfilling, successful lives.
Final Thoughts
The UC San Diego study serves as a vital reminder that autism is a complex, individualized condition that transcends traditional gender assumptions. For parents considering in-home ABA therapy services in North Carolina, this study reinforces the value of early, tailored, and evidence-driven care.
Whether through home-based or school-based ABA therapy services, the goal remains the same: to unlock every child’s potential by meeting them where they are and helping them grow.
Give your child the tools they need to grow with ABA therapy that’s built around their strengths. At Perfect Pair ABA, we’re dedicated to supporting families every step of the way. Let’s start the conversation.
Sources and Acknowledgments
This article is based on research published in Nature Human Behavior, led by Dr. Karen Pierce and her team at UC San Diego School of Medicine. The study was partially funded by the National Institutes of Mental Health and included contributions from researchers across multiple disciplines.
For more information about local autism support services including in-home ABA therapy North Carolina or school-based ABA therapy services North Carolina, reach out to trusted providers or consult developmental specialists who align their methods with the latest research findings.
FAQs
Do boys and girls show different autism traits at an early age?
Recent research from UC San Diego School of Medicine shows that toddlers diagnosed with autism show no significant gender differences in core autism traits like language development, social skills, and repetitive behaviors. This suggests that autism traits in toddlers are not influenced by gender at the time of early diagnosis.
Why are more boys diagnosed with autism than girls?
While statistics show that boys are four times more likely to be diagnosed with autism, the UC San Diego study suggests this may not reflect actual developmental differences in toddlers. Instead, this discrepancy could be due to diagnostic biases, social expectations, or small-scale studies conducted in the past.
What autism traits are evaluated in toddlers?
Autism traits assessed in early childhood include:
- Delays in language development
- Limited social interaction
- Repetitive behaviors
- Challenges with daily living skills
- Reduced eye contact or social attention
These traits help professionals determine whether a child may benefit from early intervention therapies like home ABA therapy in North Carolina.
At what age can autism traits first be noticed in children?
Autism traits can begin to appear as early as 12 to 18 months, but a comprehensive diagnosis is often made between 18 to 36 months. In-home ABA therapy services North Carolina can support toddlers soon after diagnosis to develop essential communication and behavioral skills.
Do typically developing girls show different traits than boys?
Yes. In the study, typically developing girls outperformed boys on several developmental tasks, especially those related to language, social interaction, and daily activities. However, among toddlers with autism, these gender differences were not present.
Does this study change how early intervention is approached?
Yes. It emphasizes focusing on the individual needs and developmental profile of each child rather than assuming differences based on gender. Services like aba home therapy North Carolina should be tailored based on developmental subtypes rather than sex.
How can early intervention services help toddlers with autism?
Early intervention, especially through in-home ABA therapy in North Carolina, can:
- Enhance communication skills
- Improve adaptive and social behaviors
- Reduce challenging behaviors
- Support developmental milestones
- The earlier the therapy begins, the better the outcomes for children with autism.
Should girls be screened for autism differently than boys?
No. Given the findings of this study, girls should be screened using the same criteria as boys. Early symptoms may present similarly, and delaying diagnosis due to outdated gender-based expectations could hinder early treatment.
