If One Child Has Autism, Will My Other Children Have It Too?

If you have a child with an autism spectrum disorder (ASD), it’s natural to wonder whether future children might also be on the spectrum. The chance is higher than average, but far from certain. This guide looks at what causes autism, how often it recurs in families, and how tools like whole genome sequencing (WGS) and preimplantation genetic testing (PGT) can help you make informed reproductive decisions.

What causes autism?

Autism spectrum disorder isn’t one condition with one cause. The CDC estimates that about 1 in 31 children in the U.S. is diagnosed with autism.¹

In about 30% of autistic people, a specific genetic cause can be found, such as a change in a single gene or a missing or extra piece of a chromosome.² Researchers have linked more than 200 genes to autism this way. For everyone else, autism is thought to be multifactorial: many genes, each with a small effect, plus non-genetic factors such as parental age and the prenatal environment. You can read more in What causes autism?

Some of these genetic changes are inherited from a parent. Others are new (de novo): they appear for the first time in the child and aren’t present in either parent’s DNA. That’s why autism can show up in a family with no history of it.

Step one: look for a genetic cause in your child

The single most useful thing for planning another pregnancy is finding out whether your child’s autism has an identifiable genetic cause. Testing usually includes a chromosomal microarray (which looks for missing or extra pieces of chromosomes) and autism gene panels, and more labs now offer exome or whole genome sequencing. Your child’s pediatrician or a medical geneticist can order testing, and a genetic counselor can help you understand the results.

What the result means for future children depends on what’s found:

• A genetic cause is found, and neither parent carries it. The change was most likely de novo. The chance of it happening again is generally lower than when a parent carries it, though not zero. A genetic counselor can give you a more specific estimate.
• A genetic cause is found, and a parent carries it. Each future pregnancy may have a higher chance of inheriting it. How high depends on the gene and how it’s inherited.
• No genetic cause is found. This is the most common result. It doesn’t mean the risk is back to average. When genetic testing in a family member with symptoms is negative, the chance for future children is still likely to be higher than in the general population. A medical geneticist can talk you through the specific recurrence chances in a future pregnancy.

How embryo testing can help

If you’re doing IVF, there are two ways to test embryos for genetic causes of autism:

• If your family has a known variant, PGT-M (preimplantation genetic testing for monogenic conditions) can check each embryo for that specific change.
• If there’s no known variant, or no family history at all, Orchid’s whole genome embryo screening (PGT-WGS) checks embryos for 200+ gene changes linked to autism and other neurodevelopmental disorders, as well as 50+ microdeletions and microduplications. That includes de novo changes in the embryo that wouldn’t show up in either parent. Learn more in Genetic testing for autism, intellectual disability, and other neurodevelopmental disorders.

What embryo screening can’t do

A few things to keep in mind:

• Screening can only find known genetic causes. Since most autism doesn’t have a single identifiable cause, a normal result lowers the chance of the genetic forms of autism it looks for but doesn’t rule autism out.
• It’s a screening test. The cells tested come from the part of the embryo that becomes the placenta, not the fetus itself.
• If your family’s risk is elevated but no genetic cause was found, embryo screening can still rule out other known genetic causes. It can’t remove the remaining risk.

Talking it through

Questions about recurrence are personal, and the right answer depends on your child’s test results and your family history. A genetic counselor can walk through both with you and help you decide whether embryo testing makes sense for your family.

Related Orchid guides

• What causes autism?
• Genetic testing for autism, intellectual disability, and other neurodevelopmental disorders

References

1. Centers for Disease Control and Prevention. Data and statistics on autism spectrum disorder. cdc.gov/autism/data-research
2. Woodbury-Smith M, Scherer SW. Progress in the genetics of autism spectrum disorder. Dev Med Child Neurol. 2018;60(5):445–451. doi:10.1111/dmcn.13717

This material is for general educational purposes and is not a substitute for medical advice, genetic counseling, or diagnostic testing.