Although many factors influence a child’s risk of autism, a new study “like no other” indicates parental age as an influence on the child’s risk. Previous studies identified a greater risk when the father is of advanced age but this newest study indicates both parents’ ages play a role, and so does the age gap between parents.
This study, said to be the largest ever of its kind, took an international look at parental age and autism using national health registries in five countries: Australia, Denmark, Israel, Norway, and Sweden. In these five countries:
- 5,766,794 children were born between 1985 and 2004.
- All were followed by the researchers until 2009.
- 30,902 developed autism spectrum disorders (ASD).
The research confirmed the role of paternal age but it revealed both parents’ ages are important to ASD development. The rate of autism was found to be:
- 66% higher when fathers are 50 and older than when fathers are in their 20s.
- 28% higher when dads are in their 40s instead of their 20s.
- 15% higher when mom is 40-something versus moms who are 20-something.
- 18% higher when the mother is a teenager than in her 20s.
- The ASD risk is higher still when both parents are older.
When there’s a gap of 10 years or more between parents’ ages, the risk of autism becomes:
- Highest when fathers are 35 to 40 years old and mothers are 10 years or more younger.
- High when mothers are in their 30s and fathers are 10 or more years younger.
Michael Rosanoff, also an author of the research findings, describes the study as “like no other” due to its size, which “allowed us to look at the relationship between parents’ age and autism at a much higher resolution — under a microscope, if you will.” Rosanoff is a faculty member at the Department of Epidemiology at Columbia University’s Mailman School of Public Health in New York City and is Director of Public Health Research for Autism Speaks, an organization based in New York City that is widely recognized as the world leader in advocacy and scientific research on ASD.
- Sandin, S, et al. "Autism risk associated with parental age and with increasing difference in age between the parents." Molecular Psychiatry (2015). Nature Publishing Group. Web. 17 June 2015.
- "Largest-ever study of parental age and autism finds increased risk with teen moms." EurekAlert! Autism Speaks and the American Association for the Advancement of Science, 9 June 2015. Web. 17 June 2015.