Autism run in families


Thinking about having another child?

If you have a child with autism spectrum disorder (ASD), thinking about having another child can stir up many emotions – from excitement to worry. For example, you might:

  • worry that you’ll have another child with ASD
  • be OK about having another child with ASD
  • feel guilty for wanting a child without ASD
  • feel excited at the thought of having a child with typical development
  • worry that you won’t have enough time for your child with ASD if you have a newborn
  • worry that you won’t have enough support to raise more than one child with ASD
  • worry about the impact of another child with ASD on your family relationships.

Risks of having another child with autism spectrum disorder

In general, the risk of having a child with autism spectrum disorder (ASD) is about 1 in 68, or 1.5%. But the risk goes up to approximately 20% for families who already have a child with ASD.

If a family has one child with ASD, the chance of the next child having ASD is about 15%. If the next child is a boy, that child is 2-3 times more likely to have ASD than if the child is a girl.

If a family has two or more children with ASD, the risk that the next child will also have ASD increases to about 30%. Again, the risk for boys is about 2-3 times higher than for girls.

The risks of having another child with ASD quoted above are estimates from a high-quality research study. They’re not predictions for individual families. If you’re not sure whether to have another child, it can help to talk to a genetic counsellor. Genetic counsellors can look at your individual situation, explain your risk and talk with you about your options. Ask your GP for a referral.

Risks of autism spectrum disorder characteristics

Younger siblings of children with autism spectrum disorder (ASD) are more likely than other children to have ASD-like characteristics.

This means that younger siblings are more likely to have language delays, difficulties with social communication, repetitive behaviour or narrow interests, learning difficulties and sensory sensitivities.

The risk of younger siblings having some ASD-like characteristics is about 20%.

Timing, birth order and parental age: influence on ASD risk

The less time there is between births, the higher the risk for autism spectrum disorder (ASD). This means there’s a higher risk if there’s one year between births, compared with three years, for example.

Birth order might have an effect on the severity of ASD. Second-born children with ASD seem to be more severely affected with ASD and more affected intellectually compared with first-born children with ASD.

The age of both mothers and fathers affects the risk of having a child with ASD. Just as the risk of having a child with a genetic disability such as Down syndrome increases as parents get older, so too does the risk of having a child with ASD.

We don’t know exactly what causes ASD, but in about 10% of cases, there’s a known genetic cause. Genetic influences can be inherited, but they can also happen spontaneously. For some families, ASD seems to ‘run in the family’, but for others, it appears out of nowhere.

Talking with your partner about having another child

If you’re thinking about having another child, the first step is to talk with your partner. Here are some questions that you could talk about:

  • How would you each feel about having another child with special needs?
  • What would it mean for your family?
  • How would you each feel about not having another baby?
  • Would you consider in-vitro fertilisation (IVF)?
  • Would you consider adoption?

There are other things to think about as well, like:

  • your age – the risk of having a child with a genetic disorder increases with maternal and paternal age
  • your personal or religious beliefs
  • your resources for social and financial support
  • the age gap you want between your children.

Reducing the risk of having another child with autism spectrum disorder

Some families decide to try IVF so that they can choose the sex of their baby, and opt for a female embryo to reduce the risk of autism spectrum disorder (ASD).

The laws on sex selection vary across Australia. Australian guidelines state that sex selection must not be undertaken except to reduce the risk of transmission of a serious genetic condition. These guidelines are not legally binding.

Victoria, Western Australia and South Australia have passed laws covering sex selection. They allow sex selection to prevent disorders that occur mostly, or only, in one gender – for example, muscular dystrophy, Fragile X syndrome and ASD:

  • Victorian Assisted Reproductive Treatment Authority – Preimplantation genetic diagnosis
  • WA Reproductive Technology Council – Consumer information (click ‘RTC fact sheets & publication’ and download the brochure Preimplantation Genetic Diagnosis (PGD) in WA)
  • SA Health – Assisted reproductive treatment legislation.

The Library of Congress outlines sex selection law across Australia.

There’s no right or wrong answer about having another child. It comes down to deciding what will be best for you and your family.

Autism Facts and Figures


  • In 2018 the CDC determined that approximately 1 in 59 children is diagnosed with an autism spectrum disorder (ASD).

    • 1 in 37 boys

    • 1 in 151 girls

  • Boys are four times more likely to be diagnosed with autism than girls.

  • Most children were still being diagnosed after age 4, though autism can be reliably diagnosed as early as age 2. 

  • 31% of children with ASD have an intellectual disability (intelligence quotient <70), 25% are in the borderline range (IQ 71–85), and 44% have IQ scores in the average to above average range (i.e., IQ >85).

  • Autism affects all ethnic and socioeconomic groups.

  • Minority groups tend to be diagnosed later and less often.

  • Early intervention affords the best opportunity to support healthy development and deliver benefits across the lifespan.

  • There is no medical detection for autism.


  • Research indicates that genetics are involved in the vast majority of cases.

  • Children born to older parents are at a higher risk for having autism.

  • Parents who have a child with ASD have a 2 to 18 percent chance of having a second child who is also affected.

  • Studies have shown that among identical twins, if one child has autism, the other will be affected about 36 to 95 percent of the time. In non-identical twins, if one child has autism, then the other is affected about 31 percent of the time.

  • Over the last two decades, extensive research has asked whether there is any link between childhood vaccinations and autism. The results of this research are clear: Vaccines do not cause autism.

Intervention and Supports

  • Early intervention can improve learning, communication and social skills, as well as underlying brain development.

  • Applied behavior analysis (ABA) and therapies based on its principles are the most researched and commonly used behavioral interventions for autism.

  • Many children affected by autism also benefit from other interventions such as speech and occupational therapy.

  • Developmental regression, or loss of skills, such as language and social interests, affects around 1 in 5 children who will go on to be diagnosed with autism and typically occurs between ages 1 and 3.

Associated Challenges

  • An estimated one-third of people with autism are nonverbal.
  • 31% of children with ASD have an intellectual disability (intelligence quotient <70) with significant challenges in daily function, 25% are in the borderline range (IQ 71–85).

  • Nearly half of those with autism wander or bolt from safety.

  • Nearly two-thirds of children with autism between the ages of 6 and 15 have been bullied.

  • Nearly 28 percent of 8-year-olds with ASD have self-injurious behaviors. Head banging, arm biting and skin scratching are among the most common.

  • Drowning remains a leading cause of death for children with autism and accounts for approximately 90 percent of deaths associated with wandering or bolting by those age 14 and younger.

Associated Medical & Mental Health Conditions

  • Autism can affect the whole body.

  • Attention Deficient Hyperactivity Disorder (ADHD) affects an estimated 30 to 61 percent of children with autism.

  • More than half of children with autism have one or more chronic sleep problems.

  • Anxiety disorders affect an estimated 11 to 40 percent of children and teens on the autism spectrum.

  • Depression affects an estimated 7% of children and 26% of adults with autism.

  • Children with autism are nearly eight times more likely to suffer from one or more chronic gastrointestinal disorders than are other children.

  • As many as one-third of people with autism have epilepsy (seizure disorder).

  • Studies suggest that schizophrenia affects between 4 and 35 percent of adults with autism. By contrast, schizophrenia affects an estimated 1.1 percent of the general population.

  • Autism-associated health problems extend across the life span – from young children to senior citizens. Nearly a third (32 percent) of 2 to 5 year olds with autism are overweight and 16 percent are obese. By contrast, less than a quarter (23 percent) of 2 to 5 year olds in the general population are overweight and only 10 percent are medically obese.

  • Risperidone and aripiprazole, the only FDA-approved medications for autism-associated agitation and irritability.

Caregivers & Families

  • On average, autism costs an estimated $60,000 a year through childhood, with the bulk of the costs in special services and lost wages related to increased demands on one or both parents. Costs increase with the occurrence of intellectual disability.

  • Mothers of children with ASD, who tend to serve as the child’s case manager and advocate, are less likely to work outside the home. On average, they work fewer hours per week and earn 56 percent less than mothers of children with no health limitations and 35 percent less than mothers of children with other disabilities or disorders.

Autism In Adulthood

  • Over the next decade, an estimated 500,000 teens (50,000 each year) will enter adulthood and age out of school based autism services.

  • Teens with autism receive healthcare transition services half as often as those with other special healthcare needs. Young people whose autism is coupled with associated medical problems are even less likely to receive transition support.

  • Many young adults with autism do not receive any healthcare for years after they stop seeing a pediatrician.

  • More than half of young adults with autism remain unemployed and unenrolled in higher education in the two years after high school. This is a lower rate than that of young adults in other disability categories, including learning disabilities, intellectual disability or speech-language impairment.

  • Of the nearly 18,000 people with autism who used state-funded vocational rehabilitation programs in 2014, only 60 percent left the program with a job. Of these, 80 percent worked part-time at a median weekly rate of $160, putting them well below the poverty level.

  • Nearly half of 25-year-olds with autism have never held a paying job.

  • Research demonstrates that job activities that encourage independence reduce autism symptoms and increase daily living skills.

Economic Costs

  • The cost of caring for Americans with autism had reached $268 billion in 2015 and would rise to $461 billion by 2025 in the absence of more-effective interventions and support across the life span.

  • The majority of autism’s costs in the U.S. are for adult services – an estimated $175 to $196 billion a year, compared to $61 to $66 billion a year for children.

  • On average, medical expenditures for children and adolescents with ASD were 4.1 to 6.2 times greater than for those without autism.

  • Passage of the 2014 Achieving a Better Life Experience (ABLE) Act allows tax-preferred savings accounts for people with disabilities, including autism, to be established by states.

  • Passage of autism insurance legislation in 48 states is providing access to medical treatment and therapies.

For more information, by Autism Speaks.

Preventing Autism in Pregnancy: Is it Possible?

Mila Supinskaya/

Experts are still trying to piece together what factors contribute to the development of autism. Recent research suggests that changes that occur during conception, pregnancy, and possibly even delivery may increase the risk of autism in children who are genetically predisposed to the disorder.

One study in the New England Journal of Medicine found differences in the brains of children with autism as early as the second trimester of pregnancy. While researchers haven’t been able to pinpoint a definite cause, ASD likely develops from a combination of factors. “Some cases may primarily have a genetic cause, and others may have a primarily environmental cause, but most cases probably result from the interaction of both,” says Paul Wang, M.D., senior vice president of medical research for Autism Speaks.

While you can’t do much to change genetics, you can alter your exposure to certain environmental factors that have shown a link to ASD. However, none of these lifestyle changes are absolutes—experts can’t tell you that lowering your exposure to one particular factor will lower your child’s risk.

RELATED: What Causes Autism: 6 Facts You Need to Know

“Evidence about environmental risk during pregnancy is really at its infancy, so any data-supported hypotheses must be investigated further as nothing is yet considered a certain cause,” says M. Daniele Fallin, Ph.D., director of the Wendy Klag Center for Autism and Developmental Disabilities at the Johns Hopkins Bloomberg School of Public Health. The key is for pregnant women to take some safe, proactive steps like these that can potentially protect their babies.

Can Increasing Iron Intake Prevent Autism?

A 2014 study in the American Journal of Epidemiology found that children born to iron-deficient mothers are five times more likely to develop autism. The risk increases when the mother is age 35 or older or has a metabolic condition such as obesity, high blood pressure or diabetes. Iron is crucial to fetal brain development, yet up to half of all pregnant women don’t get enough of it.

Researchers looked at the iron intake of close to 900 women during three critical stages: three months prior to becoming pregnant, throughout pregnancy and after delivery while breastfeeding. The mothers of children with autism were significantly less likely to take iron supplements before, during and/or after their pregnancies than the mothers whose children were developing typically.

This study is the first to examine the relationship between maternal iron intake and autism risk. To confirm a connection and the study’s validity, more researchers need to replicate the findings in larger research groups.

“While there’s no clear indication that iron deficiency during pregnancy causes autism, we know that iron is critical to the in utero development of a baby’s nervous system,” says Raphael Bernier, Ph.D., clinical director of the Autism Center at Seattle Children’s Hospital.

That’s why it’s important to get enough iron in your diet via foods, such as meats, seafood, eggs and iron-fortified breads and cereal, and to take an iron-fortified prenatal supplement when you’re trying to conceive and when you’re expecting.

RELATED: Autism Signs: Your Month-by-Month Guide

Can Reducing Your Exposure to Air Pollution Help?

“Perhaps the most convincing and consistent environmental association with autism risk to date is pregnancy exposure to air pollution,” says Dr. Fallin. Multiple studies have shown this connection: One by researchers at the Harvard School of Public Health found that the risk doubled for children born to women exposed to high levels of pollution, particularly in the third trimester. The higher the levels of exposure, the greater the risk.

However, that’s just part of the story.

“The challenge has become understanding what component of air pollution may be relevant, as this implicates hundreds of chemicals from multiple sources,” explains Dr. Fallin. In general, the American Lung Association recommends several ways to protect yourself from air pollution: for instance, fill your gas tank up after dark, exercise away from highly-trafficked areas and, when pollution levels are high, take your workout indoors. You can check out your daily air quality levels at

RELATED: A Day in the Life: Raising a Child with Autism

Can An Epidural Increase Autism Risk?

A 2014 French study conducted on mice and published in the journal Science suggests that the use of spinal anesthesia during labor results in higher concentrations of chloride or salt in the brains of newborn mice. The authors hypothesize that this may increase the risk of autism in humans.

High chloride levels are essential to a baby’s brain development while in utero. During labor and delivery, a baby is exposed to oxytocin, the hormone that brings on contractions. Oxytocin acts as a diuretic and naturally lowers an infant’s chloride levels. Researchers believe epidurals may interfere with the release of oxytocin causing chloride levels to remain high after birth.

The study seems to support earlier findings from a 2012 clinical trial of 60 children with autism who saw some improvements in their behaviors after taking a diuretic that lowered their chloride levels. However, the Science study on epidurals and chloride was conducted solely on mice. While animal studies are important, the findings don’t always translate to people.

“For one thing, animals don’t have symptoms of autism in the same way that people do,” says Susan Hyman, M.D., division chief of neurodevelopmental and behavioral pediatrics at the University of Rochester Medical Center in New York and chair of the American Academy of Pediatrics’ (AAP) Council of Children with Disabilities Autism Subcommittee.

RELATED: The ABCs of Asperger’s Syndrome

What’s more, the study didn’t address what happens when a mother’s labor is induced with pitocin, a synthetic version of oxytocin. “As a mother, I know that epidurals made my deliveries more comfortable,” says Dr. Hyman. “I don’t think it’s prudent to deviate from a helpful obstetrical practice based on one animal study.”

Does Maternal Weight Affect a Child’s Autism Risk?

Research from the University of Utah published in the November 2013 issue of Pediatrics suggests a potential link between excess pregnancy pounds and autism risk. The American Congress of Obstetricians and Gynecologists (ACOG) recommends women gain no more than 35 pounds during pregnancy (it’s 25 pounds if you’re already overweight). In the study, incremental 5-pound increases in weight above ACOG’s recommendation were linked to a slightly higher, yet significant risk for autism.

Previous studies indicate a possible connection to a woman’s pre-pregnancy body mass index (BMI), pregnancy weight gain, and a child’s risk of autism. One theory is that excess body fat may change a woman’s hormone levels or cause inflammation that affects fetal brain development. “Obesity rates and autism rates have both gone up over the past decades, yet that doesn’t mean the two are connected,” says Anna Maria Wilms Floet, M.D., a behavioral developmental pediatrician at the Kennedy Krieger Institute’s Center for Autism and Related Disorders in Baltimore. The bottom line: “Women should watch their weight gain during pregnancy to prevent problems like diabetes and high blood pressure,” says Dr. Wilms Floet.

Should You Reduce Your Exposure to Chemicals?

There seems to be an increased risk for ASD associated with maternal exposure to certain chemicals during pregnancy, thought a lot more research needs to be done. For instance, one recent study found environmental exposures associated with autism, specifically “traffic-related pollutants, some metals, and several pesticides and phthalates.” It can get confusing to figure out exactly which chemicals, such as those found in flame-retardants, plastics, and even cosmetics, to avoid. Talk to your doctor about what’s right for you—you might want to limit your intake of canned foods, avoid water bottles made of plastic or aluminum, and stay away from personal care products that list “fragrance” as an ingredient.

Is There a Link Between Gestational Diabetes and Autism?

An April 2015 study in the Journal of the American Medical Association (JAMA) found that mothers-to-be who are diagnosed with gestational diabetes by their 26th week of pregnancy are 63 percent more likely to have a child with autism. That means for every 1,000 women with gestational diabetes, seven of them may have a child with autism. Researchers speculate that in utero exposure to high blood sugar may affect a baby’s brain development and heighten the risk for developmental disorders.

Earlier studies also have shown a possible connection between high blood sugar during pregnancy and autism risk. The key factor may be how high blood sugar levels get. Interestingly, the JAMA study found that babies born to mothers who had type 2 diabetes before getting pregnant didn’t have a higher risk of autism, perhaps because the women were taking medication to control their blood sugar levels.

Gestational diabetes poses a number of problems for infants, including preterm labor, large birth-weight and an increased risk of obesity and type 2 diabetes later in life. Moms-to-be have a higher risk of developing high blood pressure, preeclampsia and type 2 diabetes, as well. “All expectant women should strive to keep their blood sugar under control, regardless of these study findings,” says Dr. Wilms Floet.

RELATED: We Cured Our Son’s Autism

Could Taking Certain Medications Increase Your Risk?

Researchers have found potential links between the medication a mother takes while pregnant and autism risk. For instance, use of anti-depressants (SSRIs specifically) has shown association with autism across multiple studies, says Dr. Fallin, though it remains unclear whether this link is related specifically to the drugs or to the mother’s depression itself. Also, a study in the Journal of the American Medical Association has shown that valproate, a medication used to treat epilepsy and other neurological disorders, can increase the risk for autism. It’s crucial that you work with your doctor to determine whether the benefits of any medications you take outweigh the risks. In many cases, they will: “If a mother has epilepsy, it is very important that it be controlled during pregnancy, even if that requires valproate,” explains Dr. Wang. “If the mother has a seizure while pregnant, that is potentially a much bigger risk to the fetus than the drug that controls her seizures.”

Should You Space Out Your Pregnancies?

A study in the Journal of the American Academy of Child & Adolescent Psychiatry found that pregnancies spaced between 2 and 5 years apart have the lowest risk of a child developing autism. Researchers found that those children conceived after less than 12 months were 50 percent more likely to end up with a diagnosis as compared with children conceived between that 2-and-5-year time frame, though it’s unclear why.

Meanwhile, those conceived after more than 60 months were 30 percent more likely to be diagnosed. However, keep in mind that autism risk increases with both parents’ ages at conception and that a woman’s fertility declines as she gets older. When it comes to timing, work with your doctor to determine the best plan for you and your family.

Can Folic Acid Lower Autism Risk?

A 2011 Epidemiology study found that taking prenatal vitamins three months before conception and during at least the first month of pregnancy halves a child’s autism risk. Women with a strong genetic link to the disorder who didn’t take vitamins were up to seven times more likely to have a child with autism. Additional studies suggest high levels of folic acid, a B vitamin important for brain development, are key.

All women of childbearing age (even those who aren’t trying to conceive) should get between 400 to 800 micrograms (mcg) of folic acid every day. Most women get about 150 mcg of daily folic acid from fortified foods such as breads and cereal.

A 2012 American Journal of Clinical Nutrition study suggests that women need at least four times that amount — 600 mcg — to lower autism risk. Check your vitamin’s nutrient label, and if necessary, discuss upping your folic acid intake with your doctor, and add more foods rich in folate (like lentils, spinach, and broccoli) to your diet.

RELATED: Can Folic Acid Prevent Autism?

How Does Your Health Come Into Play?

Researchers know that maternal health during pregnancy has an impact on the unborn child, and ASD is certainly no exception to this rule. “For instance, women who are severely ill and require hospitalization during pregnancy may be more likely to have children who develop autism,” says Dr. Wang. Specifically, studies have shown associations between maternal infections during pregnancy and subsequent risk for their children developing an autism spectrum disorder.

In general, women should do what they can to remain healthy during pregnancy. “This includes optimizing nutrition, taking prenatal vitamins as recommended by their obstetrician, avoiding exposure to unnecessary drugs and medications, and ensuring that their own vaccinations are up to date,” says Dr. Wang. Also, a recent study in the Journal of the American Medical Association found that gestational diabetes developed by 26 weeks is linked with an increased risk to ASD. Ask your doctor about the right plan for you and then stick with it.

  • By Dina Roth Port

Questions Remain

Previous studies have shown that only about 10% of autism cases can be explained by penetrant genes — genes in which a specific change nearly always leads to the same symptom or disease.

But most cases of autism seem to be rooted in 150 or so genes changes that are too weak to cause symptoms on their own. They only become a problem when a person has a combination of changes that tip them into a disease or a condition like autism, says Charis Eng, MD, PhD. She’s the chair of the Genomic Medicine Institute at Cleveland Clinic in Ohio. She wasn’t involved in the research.

Eng says another possibility is that the genes between brothers and sisters may be different, but they affect the same biological processes — for example, the way the brain processes sound — ultimately causing autism.

And she says it could be that some common environmental factor, like exposure to a chemical, tips a child with several weak “risk genes” into autism. Because so many different families were studied, though, it seems unlikely that it would be the same factor in every case.

Another expert says the real value of the new research is that it shows just how much we still don’t know about the condition or how children get it.

“This study confirms there are many, many different ways to get to the behaviors we call autism,” says Chris Gunter, PhD. She’s the associate director of research at the Marcus Autism Center in Atlanta. She wasn’t involved in the study.

Autism Parent, Times Two: When More than One Child in the Family has ASD

Amanda Olsen says parenting a child with autism is like being a tour guide – someone who must translate the customs and language of the nonautistic world. But when you have two children with autism, like she does, the job is considerably more complicated. That’s because many siblings with autism fall along different parts of the spectrum, and her daughters are no exception.

“I’m my children’s tour guide to the world, only I’m touring two different children in two different countries – one’s in France and one’s in Spain – at the same time. I’m having to break down the language and cultural differences and customs of two countries for them,” she explained.

If that sounds challenging, that’s because it is. The Olsens are among a subset of families that researchers call “multiplex.” That means they have multiple members with autism spectrum disorder (ASD). Among all families affected by autism, up to 19 percent have more than one child with the disorder, according to one large study.1

Multiplex families, especially those who have twins, have led to many of the breakthroughs in our understanding of autism. Four decades ago, researchers published a groundbreaking study of twins that suggested a genetic link to autism.2,3 That study, among others, helped disprove an earlier notion that autism was caused by bad parenting.

In the 21st Century, scientists studying multiplex families began identifying some of the genes altered in autism.4 They also relied on studies of identical and fraternal twins to estimate the role of environmental influences in autism.5 Unlike other siblings, twins share the same environment, their mother’s womb, at the same time.

Beyond those issues, however, scientists have devoted considerably less time to studying the day-to-day lives of families like the Olsens. A recent search turned up very few studies about stress, coping and resilience among these families. What is it like to raise two children who share an autism diagnosis, but who may have very different symptoms and needs?

An Early Arrival, An Early Diagnosis

Cindy Yeager’s twins, a boy and girl, arrived early, as twins often do. She credits a friend, an occupational therapist, with pushing her to enroll them in Maryland’s program for infants and toddlers with developmental delays. A teacher in that program noticed that her son, Aaron, flapped his hands, a behavior often seen in autism.

That led to appointments with a child psychiatrist, who diagnosed both with autism. Mrs. Yeager got the news on the same day. She took it in stride. “It wasn’t a shock because we knew something was wrong,” she said. And it offered hope: “When you get the correct diagnosis, you get the correct services. Now their teachers knew what to do.”

Fraternal twins are more likely to both have autism than siblings who are not twins. Scientists theorize that may because they share the same prenatal environment. Identical twins, who have the same genes, have the highest rate of both having autism – 88 percent – among all siblings.6

Although both Yeager twins received autism therapies and early intervention services, they travelled different paths, as siblings with ASD often do.

Hayley began talking at age 4, and entered a regular kindergarten class at 5, with a special education plan. Aaron did not develop speech, and he enrolled in an intensive program at a different school. For the Yeagers, that meant attending special education meetings – and getting to know teachers and therapists – at separate schools.

They also needed to make time for their oldest daughter, who does not have autism. In the early years, Mrs. Yeager made one-on-one time for her oldest daughter, and the twins, by taking advantage of different preschool schedules. “There was a period of time during the week when my oldest daughter was home and the twins were not, and there was a time when the twins were home, and she was not,” recalled Mrs. Yeager, who works part-time as a music assistant at her Baptist church.

Now 18, Aaron communicates with picture symbols and some sign language. He needs help with many everyday activities, such as preparing food or pouring a drink. His entire family, including his twin, pitches in, as do others.

Some activities are difficult for Aaron. “There are a lot of things we just can’t do, and we have to plan things ahead of time,” Mrs. Yeager explained. For example, Aaron has trouble sitting through a movie, so her husband may take their daughters to the theater, while Mrs. Yeager stays home with Aaron. Sometimes one of his sisters, a family friend, or a member of their church will stay with Aaron so other family members can attend church, go to an appointment, or run an errand. “We have a great church family, and they surround us with a lot of help,” she said.

And sometimes, when the family is out together, someone must bring Aaron home if he becomes overwhelmed or upset by the experience. His twin understands. “I know what he’s going through since I have autism as well,” she said. “I feel like home is the one place where he feels most comfortable.”

Hayley credits the attention of her family and others with helping her achieve. An honor student in high school, she is now studying visual communication and digital media arts at a college within commuting distance of her home. “I feel like I have been progressing more because of the people who have been helping me: my teachers, friends, people at my church, my parents and other adults. I feel like without them, I would not have made it this far in my life,” she said.

Psychologists and researchers say that families who have a network of supporters – people who can lend a hand, or an ear – cope better with stress than families who don’t.7

A Study Looks at Moms of Two Children with Special Needs

Parenting two children with special needs is particularly challenging, according to one of the few studies focused on this issue.

Researchers studied mothers who had a teenage or adult child with autism, and a second child with autism or a different disability. Those mothers had more symptoms of depression and anxiety than mothers who had just one child with a disability. They also had more problems with family cohesion (emotional bonding) and with adapting to new situations or needs. “This suggests that families who face competing demands may become less flexible in their ability to accommodate everyone’s needs,” the authors wrote.8

Educators and therapists often recommend that parents use schedules and routines to help their children with autism manage anxiety and cope with change. Perhaps being less flexible – sticking to the family’s plans – may simply be a coping skill, some researchers speculated.9

But what do you do if your children with ASD need different routines?

Two Diagnoses, One Expected and One a Surprise

If you have two people who need to have things be a certain way, they will always butt heads because all kids with autism are different.

Amanda Olsen was concerned about autism, but only in her youngest daughter, who is now 8. “She was not connecting to other people very much. She didn’t interact much. She would listen, but she wouldn’t look at you,” she said. So she made her an appointment for a psychological evaluation.

Around the same time, one of her older daughters told her that she thought she might have attention deficit disorder. So Mrs. Olsen arranged for her to be tested, as well. She was not particularly surprised when her youngest daughter received an autism diagnosis. But she had not suspected ASD in her older daughter, at least not until she had to fill out questionnaires for their evaluations. The older girl, now 13, was diagnosed with a milder form of autism, which used to be called Asperger’s Syndrome.

One common symptom of autism is an insistence on sameness – having things be a certain way, at a certain time. But two children with autism, even sisters, may not want things to be the same way, at the same time. And that can cause difficulties.

“If you have two people who need to have things be a certain way, they will always butt heads because all kids with autism are different,” explained Mrs. Olsen, who lives in Idaho. “If everyone was the same, then what I did for one child would be OK for the second child. But it’s not. One child wants to be left alone, while the other child wants to have an interaction that annoys the first child. For me, it’s a matter of stopping and helping each one to see what’s going on, and that can be exhausting, and trying to help each get control of herself.”

Mrs. Olsen educates both children at home, along with another daughter and two stepdaughters. The five girls range in age from 8 to 14. “I homeschool because I wanted to be a part of my girls’ lives. I wanted to connect with them,” she said.

The autism diagnoses led to “crazy Wednesday,” one day every week when three of her children have four therapy appointments. The two girls with ASD see occupational therapists, who help them with sensory issues and handwriting. Many people with autism are over- or under- responsive to their senses, such as noise, touch, vision, or balance. They also may have trouble with muscle or hand skills.10 Meanwhile, their sister, who does not have a diagnosis, has occupational and speech-language therapies.

Finding a Kinship with Autism

After the girls were diagnosed, a therapist told Mrs. Olsen that their autism likely “didn’t come from nowhere,” she recalled. “There’s a strong biological component.”

As she learned more about autism, she came upon a book by a woman with Asperger’s Syndrome and recognized herself in its pages. “I read a list of traits for female autism, and it was me to a ‘T.’ I realized that there is a group of people who think like me, and I fit in somewhere.” She joined online communities of women with current or past ASD symptoms, some of whom struggled as children but learned to “blend in” as adults, she said. Many, like Mrs. Olsen, were born before Asperger’s Syndrome became a diagnosis in 1994. Mrs. Olsen does not have an ASD diagnosis, nor is she seeking one.

This kinship with her daughters on the spectrum helps her relate to them in ways that people who do not have autistic symptoms may not, she said. “It’s so helpful to understand how they think.”

The Family Link

Researchers interested in autism genetics have studied the unaffected parents and siblings from families with multiple children with autism. These family members are more likely to have conversational and social difficulties than

  • families who have just one child with ASD11-13 or
  • families with typically-developing sons and daughters.14,15

That may suggest an inherited link to autism in multiplex families, but it does not mean that autism is more severe in those children. One study found that, as a group, children with autism from multiplex families had lower levels of autistic symptoms than children who were the only member of their family with ASD.16 That research involved families in the Interactive Autism Network.

Another study reached similar conclusions. In fact, it found that some children with autism from multiplex families had symptoms so mild that they fell below the threshold for autism on one test used to diagnose ASD.17

Perhaps in multiplex families, autism is the result of small genetic changes passed down from one or both parents, scientist theorize. In families with no history of autism, it’s possible that autism may arise from a significant genetic change that occurred for the first time in the child with ASD. Many genetic studies are trying to test these and other theories.

Multiple Children, Multiple Rewards

A small gesture to one of my children means the world to them.

Despite the additional challenges, parenting multiple children with autism also brings additional rewards.

For the Yeager family, caring for Aaron may have sparked a desire for independence in his sisters, Mrs. Yeager said. They like to help their brother, and pull together as a family, but they also are self-reliant, she said. “They don’t like to be helped. My oldest rarely came to us for help with schoolwork, and Hayley became that way, too,” she said. “They are more independent than some of their classmates.”

Raising children with autism can give a parent a unique perspective, an appreciation of things that might otherwise be taken for granted with typical children, Mrs. Olsen said.

For example, it may take more effort to nurture connections with those children, she said. “These children really do want to connect. And they don’t know how, and they don’t feel it, until someone breaks into their world,” she said. So she tries to break into their world by looking at it the way they do. One time she found a tiny object on the floor that seemed like trash to her. But by imagining it through her daughter’s eyes, she realized it might be a tiny treasure. When she presented the object to her daughter, the girl was instantly grateful. “A small gesture to one of my children means the world to them.”

Another time the 8-year-old told her that she loves her because, when she is pretending to be a dog, her mom acts like she really is a dog, she said. “Those are the little things that help an autistic child to connect with a loved one and feel understood. It’s an entrance to that child’s world.”

And finding that entrance is well worth it, she said. “It’s pretty darn amazing.”

Photo credits: 1) Olsen family photo, reprinted with permission; 2 – 4) iStock stock photos, 5) stock photo

When Autism Runs in the Family

Dear Amalah,

I love, love, love your blog and your smackdowns! I’m a long time reader and I really value your advice. I’ve some questions about preparing for a potentially autistic child.

I’m 26, my BF (of 7 years) is 27. We’re both students and finishing up our computer science doctoral studies. Once we’re done, we’re going to do the getting jobs, getting married and starting a family thing.

It’s the family thing that has me writing today.

My BF was diagnosed with Asperger’s Syndrome when he was in his early teens. Most people wouldn’t know it today – he’s “grown out of it”. By that I mean that his coping skills are excellent, he’s capable of avoiding situations that would overwhelm him and he presents externally as a professional, polite, quiet, funny young man. I’m very much in love. Awwww. I see some of the other side at home, with bits of anxiety, social stress, and texture & food issues. But he’s awesome and more than coping with any challenges he faces day to day.

BF’s dad (60 years old) has never been assessed, but I’d place a huge wager on him gaining a diagnosis. He’s far more Aspergers-y than BF. The same with BF’s granddad. There appears to be a lineage going on here.

So, I’m in the position of almost expecting some/all our kids to have difficulties. I’m okay with that ethically – my BF is great and happy and I’d love to have kids that are like him.

My question is one of preparation. What should I be doing to get ready for these aspects of my kids and to give them the best start I can? How early are the earliest interventions?

What should I read now? Are there any books on babies (rather than toddlers) with autism?
And what should I do with a babe in arms? Extended eye contact from day one? A big focus on sensory play?

I’m not actually panicking at the moment. I know we’ll muddle though, have wonderful successes and make dire mistakes regardless. I know I’m over analyzing the situation, and it may not happen. I like to prepare, and for me, this is like reading up about cloth diapers (love your stuff on cloth by the way!) or baby sleep. Just being prepared, you know?

Thanks so much!
PreBump Prepareer

Okay, so on the one hand, I want to thank you for NOT thinking that having a child with Autism is some horrible, terrible, scary outcome that must be avoided at all costs. (Including, like, our herd immunity. Arrrrrghdon’tgetmestartedontheantivaxxers.) Thank you for seeing that it’s not a death sentence, it’s just a difference.

On the other hand, I would really want to caution you about pre-diagnosing your babies before they even exist. Or pre-diagnosing your children before they are old enough to be really properly assessed. Autism can run in families and Autism can NOT run in families, and both families can end up with children on and off the Spectrum. But a diagnosis takes time and patience and you MUST allow a wide berth for your children’s natural pace of development and their individual quirks/personalities. An Autism diagnosis can open a lot of opportunities for support and intervention, but at the same time it’s not necessarily something you want to slap on a newborn right from the get-go because his or her eyes aren’t focusing on your face yet.

Not long after my oldest was diagnosed (initially with just Sensory Processing Disorder), I had my second baby. And of course I’d completely forgotten how long it takes babies to do…well, ANYTHING, and got myself convinced that since my first baby did X and Y and Z and turned out to be “different,” any time my second baby did X or Y or Z, it meant we were CLEARLY headed down the exact same quirky, sensory, developmentally delayed path.

We were not, at all. Other than really, really hating the dentist and an impressive ability to ignore me asking him to put on his shoes, Ezra has absolutely no sensory or social issues.

And then I had a third baby and did the same damn thing all over again. To the point of Googling whether or not you could “tell” if a newborn has Autism.

Spoiler alert: No, you cannot. In fact, if I did learn anything from my sleep-deprived, neurotic web surfing, is that a diagnosis of an Autism Spectrum Disorder (ASD) made when the child is TOO YOUNG should be treated with measured caution, and the child should be reassessed when they are older to account for normal lags and jags in early childhood development.

In retrospect, sure. There were “things” my oldest son as a baby did that maaaayyyybeee were a sign that he’d eventually land on the Spectrum? Things his brothers didn’t really do? But then each of them also had their own unique set of baby quirks too. All of my toddlers lined up their toys. My youngest toe-walked a little bit, as did my oldest. So who could possibly have known that he alone had Autism? We certainly didn’t, and I don’t regret that or feel like we missed some crucial intervention or opportunity because we waited until he was two years old and had a documented speech delay, would freak out if his trains weren’t lined up perfectly, and had a pronounced toe-walking habit. I’m actually glad I never thought to stress out over his fascination with ceiling fans as an infant, because WTF would we have even done at that point? The baby likes ceiling fans, let him stare at ceiling fans.

But just as ASD/Asperger’s is a part of who my son simply IS, I’m going to guess that being a VERY VERY WELL-PREPARED PLANNING TO PLAN person is simply who YOU are, and nothing I say here is going to remove the urge to read/research All of The Things. So…maybe just reframe this. Instead of trying to find resources on “babies with Autism,” I suggest you read and research more about Asperger’s/ASD in general, across any age. It will help you understand what your husband experiences, and maybe shed light on how he achieved such a great outcome. (Despite not being officially diagnosed until his teens!)

I’m a big fan of the guys from Asperger Experts — they both have Asperger’s, and are able to very clearly explain and articulate what day-to-day life is like for them, and how I as a parent can make day-to-day life better and easier for my child. They also have videos and coaching materials aimed at older teens and adults, which I imagine my son will find useful at some point.

And if and when you do have a baby, please…just enjoy him or her. Love him or her. Let him or her simply be PERFECT for as long as you can. Try not to constantly scan his or her face for “signs” or view your job as a parent to include being an occupational therapist and psychiatrist and developmental pediatrician all rolled into one. Even if you do have a child on the Autism Spectrum (and hey, technically we’re ALL on the Spectrum), you’ll clearly be a capable, educated person who knows what Early Intervention IS and can probably track down the phone number on your county’s website. They’ll be there if and when you need them.

And BONUS: Don’t forget you’ll be co-parenting with a living success story and a bona fide expert in life on the Spectrum.

More on Asperger’s Syndrome From Alpha Mom:

  1. To Label or Not To Label, That is the Question
  2. Dealing With a New Diagnosis
  3. In Hindsight: Child Development and When Should We Worry?

Data & Statistics on Autism Spectrum Disorder


CDC has a new data visualization tool that lets users map and graph ASD data. Visit the website and explore the data!

  • About 1 in 59 children has been identified with autism spectrum disorder (ASD) according to estimates from CDC’s Autism and Developmental Disabilities Monitoring (ADDM) Network.
  • ASD is reported to occur in all racial, ethnic, and socioeconomic groups.
  • ASD is about 4 times more common among boys than among girls.
  • Studies in Asia, Europe, and North America have identified individuals with ASD with an average prevalence of between 1% and 2%. ]
  • About 1 in 6 children in the United States had a developmental disability in 2006-2008, ranging from mild disabilities such as speech and language impairments to serious developmental disabilities, such as intellectual disabilities, cerebral palsy, and autism.
Identified Prevalence of Autism Spectrum Disorder

ADDM Network 2000-2014 Combining Data from All Sites

Learn more about prevalence of ASD “

Learn more about the ADDM Network “

Learn more about MADDSP “

Risk Factors and Characteristics

  • Studies have shown that among identical twins, if one child has ASD, then the other will be affected about 36-95% of the time. In non-identical twins, if one child has ASD, then the other is affected about 0-31% of the time.
  • Parents who have a child with ASD have a 2%–18% chance of having a second child who is also affected.
  • ASD tends to occur more often in people who have certain genetic or chromosomal conditions. About 10% of children with autism are also identified as having Down syndrome, fragile X syndrome, tuberous sclerosisexternal icon, or other genetic and chromosomal disorders.
  • Almost half (44%) of children identified with ASD has average to above average intellectual ability.
  • Children born to older parents are at a higher risk for having ASD.
  • A small percentage of children who are born prematurely or with low birth weight are at greater risk for having ASD.
  • ASD commonly co-occurs with other developmental, psychiatric, neurologic, chromosomal, and genetic diagnoses. The co-occurrence of one or more non-ASD developmental diagnoses is 83%. The co-occurrence of one or more psychiatric diagnoses is 10%.


  • Research has shown that a diagnosis of autism at age 2 can be reliable, valid, and stable.
  • Even though ASD can be diagnosed as early as age 2 years, most children are not diagnosed with ASD until after age 4 years. The median age of first diagnosis by subtype is as follows.
    • Autistic disorder: 3 years, 10 months
    • ASD/pervasive developmental disorder (PDD): 4 years, 8 months
    • Asperger disorder: 5 years, 7 months
  • Studies have shown that parents of children with ASD notice a developmental problem before their child’s first birthday. Concerns about vision and hearing were more often reported in the first year, and differences in social, communication, and fine motor skills were evident from 6 months of age.

Economic Costs

  • The total costs per year for children with ASD in the United States were estimated to be between $11.5 billion – $60.9 billion (2011 US dollars). This significant economic burden represents a variety of direct and in-direct costs, from medical care to special education to lost parental productivity.
  • Children and adolescents with ASD had average medical expenditures that exceeded those without ASD by $4,110–$6,200 per year. On average, medical expenditures for children and adolescents with ASD were 4.1–6.2 times greater than for those without ASD. Differences in median expenditures ranged from $2,240 to $3,360 per year with median expenditures 8.4–9.5 times greater.
  • In 2005, the average annual medical costs for Medicaid-enrolled children with ASD were $10,709 per child, which was about six times higher than costs for children without ASD ($1,812).
  • In addition to medical costs, intensive behavioral interventions for children with ASD cost $40,000 to $60,000 per child per year.

Doctors don’t know what causes autism, but they believe genes play the biggest part in whether a child is born with it.

In rare cases, doctors also say, a baby can be born with birth defects if the mother was exposed to certain chemicals while she was pregnant. But doctors can’t find out, during your pregnancy, if your baby will have autism.

While you can’t prevent having a child with an autistic disorder, you can increase your odds of having a healthy baby by doing these lifestyle changes:

Live healthy. Have regular check-ups, eat well-balanced meals, and exercise. Make sure you have good prenatal care, and take all recommended vitamins and supplements.

Don’t take drugs during pregnancy. Ask your doctor before you take any medication. This is especially true for some anti-seizure drugs.

Avoid alcohol. Say “no” to that glass of wine — and any kind of alcoholic beverage — while you’re pregnant.

Seek treatment for existing health conditions. If you’ve been diagnosed with celiac disease or PKU, follow your doctor’s advice for keeping them under control.

Get vaccinated. Make sure you get the German measles (rubella) vaccine before you get pregnant. It can prevent rubella-associated autism.

U.S. autism rate up 15 percent over two-year period

ASD is a developmental disorder characterized by social and communication impairments, combined with limited interests and repetitive behaviors. Early diagnosis and intervention are key to improving learning and skills. Rates have been rising since the 1960s, but researchers do not know how much of this rise is due to an increase in actual cases. There are other factors that may be contributing, such as: increased awareness, screening, diagnostic services, treatment and intervention services, better documentation of ASD behaviors and changes in diagnostic criteria.

For this new report, the CDC collected data at 11 regional monitoring sites that are part of the Autism and Developmental Disabilities Monitoring (ADDM) Network in the following states: Arizona, Arkansas, Colorado, Georgia, Maryland, Minnesota, Missouri, New Jersey, North Carolina, Tennessee and Wisconsin. The Maryland monitoring site is based at the Johns Hopkins Bloomberg School of Public Health in Baltimore.

This is the sixth report by the ADDM Network, which has used the same surveillance methods for more than a decade. Estimated prevalence rates of ASD in the U.S. reported by previous data were:

  • one in 68 children in the 2016 report that looked at 2012 data
  • one in 68 children in the 2014 report that looked at 2010 data
  • one in 88 children in the 2012 report that looked at 2008 data
  • one in 110 children in the 2009 report that looked at 2006 data
  • one in 150 children in the 2007 report that looked at 2000 and 2002 data

“The estimated overall prevalence rates reported by ADDM at the monitoring sites have more than doubled since the report was first published in 2007,” says Dr. Li-Ching Lee, PhD, ScM, a psychiatric epidemiologist with the Bloomberg School’s departments of Epidemiology and Mental Health and the principal investigator for Maryland-ADDM. “Although we continue to see disparities among racial and ethnic groups, the gap is closing,” Lee says.

ASD prevalence was reported to be approximately 20 to 30 percent higher among white children as compared with black children in previous ADDM reports. In the current report, the difference has dropped to 7 percent. In addition, approximately 70 percent of children with ASD had borderline, average or above average intellectual ability, a proportion higher than that found in ADDM data prior to 2012.


Some trends in the latest CDC report remain similar, such as the greater likelihood of boys being diagnosed with ASD, the age of earliest comprehensive evaluation and presence of a previous ASD diagnosis or classification. Specifically, non-white children with ASD are being identified and evaluated at a later age than white children. The majority of children identified with ASD by the ADDM Network (80 percent) had a previous ASD diagnosis or a special educational classification.

In Maryland, the prevalence of ASD was higher than in the network as a whole. An estimated one in 50 children (2 percent) was identified as having ASD — one in 31 among boys and one in 139 among girls. The data were derived from health and special education records of children who were eight years old and living in Baltimore County in 2014.

Lee notes, similar to previous reports, the vast majority of children identified with ASD in Maryland had a developmental concern in their records by age three (92 percent), but only 56 percent of them received a comprehensive evaluation by that age. “This lag may delay the timing for children with ASD to get diagnosed and to start receiving needed services,” says Lee, an associate director of the school’s Wendy Klag Center for Autism and Developmental Disabilities.

The causes of autism are not completely understood; studies show that both environment and genetics may play a role. The CDC recommends that parents track their child’s development and act quickly to get their child screened if they have a concern. Free checklists and information for parents, physicians and child care providers are available at:

A full copy of the report, “Prevalence of Autism Spectrum Disorder Among Children Aged 8 Years — Autism and Developmental Disabilities Monitoring Network, 11 Sites, United States, 2014” is available on the CDC website:

A copy of the Community Report with individual state statistics is available at:

Study Confirms: Autism Wandering Common & Scary

A new study confirms what many parents know well: Wandering by children with autism is common, dangerous and puts tremendous stress on families.

Using parent surveys, the researchers found that nearly half of children with autism spectrum disorder (ASD) attempt to wander or bolt from a safe, supervised place. More than half of these wandering children go missing – often into dangerous situations.

Importantly, the researchers found evidence that autism-related wandering does not stem from inattentive parenting. It also found that half of all parents had received no help or guidance on how to deal with the problem.

The study appears online today in the journal Pediatrics. Autism Speaks funded the research through its support of the Interactive Autism Network (IAN), an online project bringing together families affected by autism.

For the study, researchers sent questionnaires to IAN families, asking them to describe wandering after age 4 in children with autism and their unaffected siblings. Questions included whether a child had ever wandered or gone Frequency of wandering for children with ASD and siblings without ASD.missing and what promoted the disappearance. Parents also described the level of stress that wandering places on their family. In all, the survey captured information on 1,218 children affected by ASD and 1,076 normally developing siblings.

Nearly half (49 percent) of parents reported that a child with ASD had attempted to wander or run away at least once after age 4. Over half of these wandering children (53 percent) went missing long enough to cause worry. In addition, 65 percent of these incidents involved a close call with traffic. Nearly a quarter (24 percent) involved a close call with drowning.

A clear distinction emerged in families who also had typically developing children. Between ages 4 and 7, only 11 percent of unaffected siblings wandered, versus 46 percent of those with ASD. From age 8 through 11, just 1 percent of unaffected siblings wandered, compared with 27 percent of those with ASD.

“It’s important to see that the high frequency of wandering in affected children contrasts to relatively little wandering in their unaffected siblings,” says Autism Speaks Assistant Director of Public Health Research Amy Daniels, Ph.D.

This clearly communicates that wandering has little to do with parenting style and more to do with the nature of a child’s autism.

Dr. Daniels co-authored the study, which she helped conduct before coming to Autism Speaks this year.

The study also provided a snapshot of the where, when and why of wandering among children with autism. Overall, wandering increased with autism severity. Most commonly, children wandered from their own home or one they were visiting. They also wandered from stores and schools.

When asked why their child with autism wandered, just over half of parents indicated that their child “simply enjoys running and/or exploring.” Other common reasons included heading to a favorite place, escaping an anxious situation, escaping uncomfortable sensory stimuli or pursuing a special interest (each reported by roughly a third of parents).

The survey also confirmed that wandering creates great stress for families. Over half of parents (56 percent) indicated it was their child’s most stressful behavior. Nearly half (43 percent) reported that it interfered with their ability to sleep at night. Sixty-two percent reported that it prevented them from attending or enjoying activities away from home.

Despite this high toll, half of parents said they’d received no guidance whatsoever on preventing or addressing the problem.

“This study underscores the need to develop ways to protect children who are unexpectedly without supervision or in an unsafe space, to help locate children when they wander and to prevent wandering from ever happening,” says Dr. Daniels. “Families can develop safety plans for their children and work with teachers, police and other members of the community to educate them about autism and their children’s risk of wandering. “

How likely is it that I could have another child with autism?

“I am a parent of a young boy with autism. I don’t know of any other individuals in my family with an autism diagnosis but am considering having more children. How likely is it that I could have another child with autism?”

Answered by Scott M. Myers, MD, FAAP, Neurodevelopmental Pediatrician, Geisinger Autism & Developmental Medicine Institute, Lewisburg, PA.

This important question is asked by many parents who are considering having more children. The answer depends greatly on whether a specific genetic cause of your child’s autism spectrum disorder (ASD) has been identified. Currently, genetic testing can identify a specific cause in approximately 15% of children with ASD, and this information allows more accurate counseling about recurrence risk for the individual family. In instances where a genetic cause is unknown, different types of studies have found varying rates of recurrence risk.

Epidemiologic studies investigate the characteristics of diseases or disorders in large populations using rigorous statistical methods. These studies have found that 4-7% of families had more than one child with an ASD (Chakrabarti & Fombonne, 2001; Gronborg, Schendel, & Parner, 2013). The largest and most recent population-based study, which included over 1.5 million children born in Denmark between 1980 and 2004, found an overall recurrence risk of 7% (Gronborg et al., 2013). This type of study has many advantages, such as avoiding bias introduced by increased parental awareness and differential participation when there is already a child with an ASD in the family. However, this type of study design may lead to underestimation of recurrence risk because of missed cases in the populations studied and the tendency of couples with an affected child to stop having children, which is known as “stoppage.”

Rather than including all children in a given region, some research focuses only on children with ASD and their siblings. Studies that include all siblings born before and after the child who has ASD have found the ASD recurrence risk to be 6-10% (Bolton et al., 1994; Chudley, Guitierrez, Jocelyn, & Chodirker. 1998; Sumi, Taniai, Miyachi, & Tanemura, 2006); however, like epidemiologic studies, they may underestimate recurrence risk due to stoppage. Studies that only include families with later-born siblings to avoid the stoppage effect have reported higher recurrence rates of 8-19% (Constantino, Zhang, Frazier, Abbacchi, & Law, 2010; Ozonoff et al., 2011; Ritvo, Jorde, Mason-Brothers, Freeman, Pingree, Jones, & Mo, 1989). The highest rate of recurrence, almost 19%, was found in a large, prospective study of younger siblings of children with an ASD who were recruited in infancy and monitored closely (Ozonoff et al., 2011). However, when families that already had two or more children with ASD were excluded, the recurrence rate was 13.5% in this study.

Therefore, the short answer is that for a couple with one child with ASD of unknown cause, the current best estimate of recurrence in a subsequent child is approximately 10% based on the most recent and well-designed studies. Because this is much higher than the 1% chance of any random couple in the general population having a child with ASD, the younger siblings of a child with ASD should be monitored closely and screened for ASD at well-child visits as recommended by the American Academy of Pediatrics (Johnson, Myers, & Council on Children With Disabilities, 2007). If a couple already has two or more children with an ASD, the chance of a subsequent child having an ASD may be as high as 32-35% (Ozonoff et al., 2011; Ritvo et al., 1989).

Two other points related to recurrence rates are worth noting. First, some studies have suggested that the risk of ASD in later-born children is higher if the first affected child was a girl and lower if the first affected child was a boy (Ritvo et al., 1989; Jorde et al., 1991; Sumi et al., 2006). Conversely, other more recent studies have not found that the sex of the first affected child is associated with a significant difference in recurrence risk in subsequent children (Goin-Kochel et al., 2007; Constantino et al., 2010; Ozonoff et al., 2011). Thus, at present, the available evidence does not argue convincingly for adjusting recurrence risk based on the sex of the first child with ASD. Second, some studies have found that 20-25% of siblings who do not meet criteria for an ASD do have a history of language impairment or delay (Constantino et al., 2010; Lindgren, Folstein, Tomblin, & Tager-Flusberg, 2009). The risk of language delay in a subsequent child is not included within the ASD recurrence rate estimates reported above.

It is important to understand that the recurrence estimates measured in these studies are based on group averages and that unless the specific genetic cause of the first child’s ASD is known, it is not possible for a family to receive specific counseling about their individual level of risk. This is one reason why it is important that families be offered genetic testing for their child with ASD. When the physician does not suspect a specific disorder or syndrome based on examination, the current recommendation is to complete chromosomal microarray analysis and Fragile X molecular analysis (Manning & Hudgins, 2010; Miller et al., 2010). These tests, which are typically performed on a blood sample obtained from the affected child, identify a specific cause in approximately 15% of individuals with ASD, and this number is likely to increase as newer technologies such as whole exome sequencing and whole genome sequencing become more widely available and utilized for clinical purposes (Abrahams & Geshwind, 2008; O’Roak, et al., 2012; Sanders et al., 2012).

For families in which a genetic cause of ASD has been identified, the recurrence risk varies significantly depending on the type of genetic problem found. For example, the risk could be as high as 50%, as in the case of a child who inherits a specific extra segment of DNA on the 15th chromosome (15q11-q13) from his/her mother. Or, the recurrence risk could be as low as 1% or less if the child has a small “missing” or “extra” section of DNA (called a microdeletion or microduplication) that is not carried by either parent.

It is also important to understand that if a specific cause is not found upon genetic testing, it does not mean that the cause is not genetic, just that it cannot be identified currently using the tests that were completed.

In summary, for a couple with one child with an ASD of unknown cause, the current best estimate of the risk of a subsequent child having ASD is approximately 10% based on group averages. Any couple with questions about recurrence risk should pursue genetic counseling so that the information can be tailored to their specific situation. Because of the increased risk of ASD, all younger siblings of an affected child should be monitored through routine administration of ASD screening tools to facilitate earlier identification and intervention.

Chakrabarti, S., & Fombonne, E. (2001). Pervasive developmental disorders in preschool children. JAMA, 285, 3093-3099.

Manning, M., & Hudgins, L. (2010). Array-based technology and recommendations for utilization in medical genetics practice for detection of chromosomal abnormalities. Genetics in Medicine, 12, 742-745.

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