Is that me? Heredity and a parent's own diagnosis

Somewhere between the third article and the fourth, you stopped reading about your child and started reading about yourself. The sensory stuff. The exhaustion after social events. The lists, the lateness, the way you have always needed things a certain way. You are not imagining the resemblance, and you are far from alone.

Why this happens: heredity

A study following more than two million children in five countries estimated autism heritability at about 80 percent. ¹ For ADHD, a major genetics review puts heritability at roughly 74 percent, close to three-quarters. ²

Heritability is a population number, not a prediction for one family. It does not mean 80 percent of autistic children have an autistic parent. It means that the differences between people in whether they are autistic are mostly down to inherited genes, which is why the traits so often run through families, sometimes named, often not.

Research also shows the two conditions share genetic ground. Rare variants that raise ADHD likelihood overlap with autism risk genes, and infant studies find related early sensory patterns across both family histories. ^{4, 5} So a parent with ADHD reading about an autistic child, or the reverse, is seeing a real overlap, not a coincidence.

The "second generation" effect

The site's research compendium calls this the second-generation effect: a child's assessment becomes the parent's first honest look at themselves. Two things make it especially common right now.

First, most of today's parents grew up when autism was diagnosed narrowly and ADHD was mostly noticed in disruptive boys. Girls, quiet children and anyone who could hold it together at school were missed, so a whole generation reached adulthood without a name for their wiring. See Girls, quiet kids and masking.

Parenting may lead you to reconsider your own routines, sensory needs or attention. If those questions matter to you, bring concrete examples to a clinician; this page cannot tell you whether you are autistic or have ADHD.

When describing your child to a clinician, include everyday examples even when those behaviours seem familiar within your family.

The counter-intuitive part: similarity may help

Here is the finding that changes the story from something to fear into something to use. A 2025 study followed 222 parent-child pairs in a family-history cohort and measured how similar parent and child were on autism and ADHD traits. Mother-child similarity on autism traits predicted better social functioning and psychological well-being in the child at age 3; father-child similarity on autism traits also went with better social functioning. The authors suggest parent-child neurodevelopmental similarity may act as a protective factor. ³

It is one study in one cohort, and it needs replicating. It does not establish why the association occurred or predict an individual family’s experience.

What this changes for your family

Nothing about your child's path. The referral, the assessment, the supports: all the same. See Autism, ADHD and language delay at age 2.

A lot about how you run the house. Consider which routines and supports each person in the household prefers; shared traits do not guarantee shared needs. See Parent burnout and co-regulation first.

Guilt, which deserves a direct answer. Many late-recognized parents feel they "passed it on". You did not choose your genes any more than your eye colour, and the same genes gave your child the parent most likely to understand them. Autism is not damage. It is a way of being wired that comes with real support needs and real strengths, in you and in them. Treating your own traits with contempt teaches your child to do the same with theirs. See What autistic adults wish parents knew.

Grandparents and siblings. Heredity often explains a grandparent's "he'll grow out of it, his father was just like that". The father was, and did not grow out of it; he grew around it. Siblings may share traits too, and the Siblings and fathers page covers that. How to talk about all of it is on Telling family, grandparents and your child.

Do you need an assessment yourself?

Only if it would change something. Reasons parents give:

• ADHD treatment. Evidence for short-term benefit of ADHD medication in adults is moderate, and for many parents it is the difference between managing the household and drowning in it. That requires a diagnosis. ⁶
• Accommodations at work, which usually require documentation.
• Understanding, which for some people needs the official word and for others does not.

In Quebec, public adult autism assessment is very limited; Autisme Montréal reports a single RAMQ-covered hospital clinic with a waiting list currently closed to adults, and private assessment costs money. ⁷ There is no deadline. Some parents self-identify and stop there; some pursue assessment years later, when the child's supports are running and there is finally room. Both are reasonable.

This week

Sources

1. Association of genetic and environmental factors with autism in a 5-country cohort (2019) ↩1
2. Genetics of attention deficit hyperactivity disorder (2019) ↩1
3. Parent-child similarity on autism and ADHD traits and children's social functioning and psychological well-being at 3 years (2025) ↩1
4. Rare coding variants confer high ADHD risk and implicate neuronal biology (2025) ↩1
5. Cortical markers of excitation/inhibition balance and sensory responsivity from infancy in autism and ADHD family history (2025) ↩1
6. Benefits and harms of ADHD interventions: umbrella review and platform for shared decision making (2025) ↩1
7. How to get a diagnosis (2026) ↩1