Is autism more likely when both parents are of advanced age?

PostedDecember 2, 2025

UpdatedDecember 2, 2025

ByMy Patient Advice

Author: Hannah Smith, MSc | Reviewed by: Dr. Rebecca Fernandez, MBBS

Recent research suggests that combined parental age and autism risk may be more than the sum of its parts. When both the mother and father are older, typically defined as over 35 for mothers and over 40 for fathers, the risk of autism in their child may increase slightly. This has led scientists to explore whether an additive risk or interaction effect is at play.

The connection between combined parental age and autism risk appears to stem from a mix of age-related genetic changes and environmental influences. Both egg and sperm are affected by ageing in different ways, potentially increasing the likelihood of de novo mutations, hormonal changes, or immune-related complications during pregnancy.

Exploring Parental Age Interaction

Here is what the data reveals about how maternal and paternal age might work together:

Additive risk from dual parental ageing

Studies show that when both parents are older, the additive risk may compound, even if each parent’s individual risk factor is modest. This cumulative effect is especially relevant in cases where there are other contributing variables, such as family history or complications during pregnancy.

Parental age interaction and developmental timing

The parental age interaction may influence key neurodevelopmental windows, with some evidence suggesting that timing and quality of fertilisation, as well as early immune responses, differ in older couples. These differences may affect brain development during gestation.

While the increase in risk is statistically modest, awareness of combined parental age and autism risk can help inform prenatal planning and support conversations with healthcare providers.

Visit providers like Autism Detect for personal consultations to understand how parental health and genetic background impact your child’s development and how to support effective sensory regulation and comfort.

For a deeper dive into the science, diagnosis, and full treatment landscape, read our complete guide to Advanced Parental Age.

Hannah Smith, MSc

Author

Hannah Smith is a clinical psychologist with a Master’s in Clinical Psychology and over three years of experience in behaviour therapy, special education, and inclusive practices. She specialises in Applied Behavior Analysis (ABA), Cognitive Behavioural Therapy (CBT), and inclusive education strategies. Hannah has worked extensively with children and adults with Autism Spectrum Disorder (ASD), ADHD, Down syndrome, and intellectual disabilities, delivering evidence-based interventions to support development, mental health, and well-being.

All qualifications and professional experience stated above are authentic and verified by our editorial team. However, pseudonym and image likeness are used to protect the author's privacy.

Dr. Rebecca Fernandez, MBBS

Reviewer

Dr. Rebecca Fernandez is a UK-trained physician with an MBBS and experience in general surgery, cardiology, internal medicine, gynecology, intensive care, and emergency medicine. She has managed critically ill patients, stabilised acute trauma cases, and provided comprehensive inpatient and outpatient care. In psychiatry, Dr. Fernandez has worked with psychotic, mood, anxiety, and substance use disorders, applying evidence-based approaches such as CBT, ACT, and mindfulness-based therapies. Her skills span patient assessment, treatment planning, and the integration of digital health solutions to support mental well-being.

All qualifications and professional experience stated above are authentic and verified by our editorial team. However, pseudonym and image likeness are used to protect the reviewer's privacy.