What Is the Broad Autism Phenotype?

Traits, Testing, and How It Differs From Diagnosed Autism

The broad autism phenotype (BAP), also called broader autism phenotype, describes a range of traits that resemble autism, but are considered subclinical, or not enough to qualify for a diagnosis of autism spectrum disorder.

For a diagnosis of autism spectrum disorder, specific social, verbal, nonverbal, relational, behavioral, and sensorial criteria must be met. However, with the BAP, traits may be seen from a few, or all categories, on a milder scale.

A child lining up crayons.

Kinzie Riehm / Getty Images

This article explains the broad autism phenotype and the traits associated with it. It also discusses how the BAP is diagnosed, and the differences between these traits and autism spectrum disorder.

What Are Broader Autism Phenotype Characteristics?

Individuals with the BAP traits have symptoms of autism, just on a milder scale. These traits typically do not greatly interfere with an individual's quality of life and are not enough to trigger a diagnosis of autism spectrum disorder.

Keep in mind that characteristics of the BAP and symptoms of autism can appear within the first year of a child's life.

Broad autism phenotype symptoms and traits may include:

  • Difficulties with verbal and nonverbal communication
  • Delayed language development during childhood
  • Rigid tendencies, like the need for routine
  • Aloofness
  • Over or under-responsiveness to sensory input
  • Fixating on specific interests

The BAP is not an official diagnosis. Instead, it describes a cluster of traits. These traits can show up differently in each unique individual.

Unlike a diagnosis of autism spectrum disorder where specific criteria must be met, the BAP has much more wiggle room in terms of how it manifests.

Autism Spectrum Disorder vs. Broad Autism Phenotype

Autism Spectrum Disorder
  • Repetitive speech patterns and idiosyncratic phrases

  • May have reading comprehension difficulties

  • Persistent difficulties in social/emotional interactions and communication

  • Inflexible and ritualized verbal and non-verbal behaviors

  • Highly fixated, rigid, inflexible interests

Broad Autism Phenotype
  • May have delayed language

  • May have difficulty with reading and spelling

  • May take a long time to put together thoughts

  • May show rigid thinking and prefer routine

  • May fixate on objects/interests

How Is the Broad Autism Phenotype Diagnosed?

To better understand if you have the BAP, your healthcare provider or mental health clinician may ask you to take tests like the Social Responsiveness Scale or the Broad Autism Phenotype Questionnaire.

You may answer the test alone, or fill it out with the help of your healthcare provider or mental health clinician. People using the questionnaire are asked to rank themselves on a scale of 1-5 on such statements as:

  • I like being around other people.
  • I find it hard to get my words out smoothly.
  • I am comfortable with unexpected changes in plans.
  • I would rather talk to people to get information than to socialize.

Unfortunately, the results of these evaluative questionnaires can vary radically. Because the BAP isn't an official diagnosis, it can be difficult to know if you have it. Working with a healthcare provider or mental health clinician who you know and trust can help give you insight into the traits or symptoms you're experiencing.

Does the BAP qualify a child for an IEP?

A child will not likely qualify for an IEP, or an individualized education program, if they have the broad autism phenotype. However, children diagnosed with autism may be eligible for an IEP or other services.

Can You Be Diagnosed With Autism If You Have the BAP?

Signs of autism can show up within the first year of a child's life. With that said, an individual may exhibit traits of the BAP, and later on, when the challenges of school or work come up, be later diagnosed with autism spectrum disorder.

But, it's also important to keep in mind that many people have traits of the BAP and will not go on to be diagnosed with autism spectrum disorder.

Is the BAP Genetic?

Studies have shown a very strong genetic, or hereditary, component with the BAP. Specifically, studies show that:

  • Individuals related to someone with autism spectrum disorder are more likely than the general public to exhibit signs or traits of autism or the BAP.
  • Parents who have traits of the BAP are more likely than parents who don't to have multiple children with autism spectrum disorder.
  • Families with more than one child with autism spectrum disorder are more likely than families with one child with autism spectrum disorder to have relatives with the BAP.

Your healthcare provider or mental health clinician may ask you about your family history during the diagnostic process to see if others within the family have autism spectrum disorder or the BAP.


The BAP describes a range of traits that resemble autism spectrum disorder, but aren't enough to trigger an official diagnosis.

You may find out that you have the BAP by speaking with a mental health clinician or your healthcare provider. They may have you take a specific questionnaire to provide further insight.

A Word From Verywell

If you think that you or a loved one may have the broad autism phenotype or undiagnosed autism spectrum disorder, you may want to consider seeing your healthcare provider or a mental health clinician for further evaluation.

By understanding the broad autism phenotype you also may be more aware of potential signs of autism spectrum disorder. This insight can help you or a loved one get support as soon as possible.

Frequently Asked Questions

  • What is broad autism phenotype questionnaire?

    It is a list of 36 questions about social, verbal, non-verbal, and restricted or repetitive behaviors. Each item has a rating scale to help identify traits of the BAP.

  • What is the phenotype of a person with diagnosed autism?

    The phenotype, or observable traits, associated with autism can vary. Social, non-verbal, verbal, behavioral, sensorial, and relational signs may be observed.

  • What is the female autism phenotype?

    This is the expression of autism in assigned females. Some theories suggest that the diagnostic criteria doesn't account for the ways assigned females express some symptoms of autism.

  • Can you have traits of autism without having autism?

    Yes. It is possible to have traits of autism without qualifying for a diagnosis of autism spectrum disorder.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention. Signs and symptoms of autism spectrum disorder.

  2. Godoy-Giménez, M., González-Rodríguez, A., Estévez, A.F. et al. Applying a rasch model to the broad autism phenotype questionnaire: item severity analysis and differential test functioning of the english and spanish versionsCurr Psychol. doi:10.1007/s12144-022-02789-6

  3. Rubenstein E, Chawla D. Broader autism phenotype in parents of children with autism: a systematic review of percentage estimatesJ Child Fam Stud. 2018;27(6):1705–1720. doi:10.1007/s10826-018-1026-3

  4. Nemours KidsHealth. Individualized education programs (IEPs).

  5. Gerdts J, Bernier R. The broader autism phenotype and its implications on the etiology and treatment of autism spectrum disordersAutism Res Treat. 2011;2011:545901. doi:10.1155/2011/545901

  6. Sasson NJ, Lam KSL, Childress D, Parlier M, Daniels JL, Piven J. The broad autism phenotype questionnaire: prevalence and diagnostic classification: the BAPQ in a large community-based sampleAutism Res. 2013;6(2):134-143. doi:10.1002/aur.1272

  7. Hull L, Petrides KV, Mandy W. The female autism phenotype and camouflaging: a narrative reviewRev J Autism Dev Disord. 2020;7(4):306-317. doi:10.1007/s40489-020-00197-9

By Lisa Jo Rudy
Lisa Jo Rudy, MDiv, is a writer, advocate, author, and consultant specializing in the field of autism.