- the age of mother and father and
- even a certain age difference between mother and father
The older a mother gives birth to a baby, the more likely it will develop autistic characters. A 40 year old mother has a 50% greater chance of having an autistic child than a mother in the age of 25 - 29 years.
The risk of fathers which are older than 40 years is only significant higher if the mother is younger than 30 years. The risk is twice as likely that the kid will develop autism signs than if the father would be 25 - 29 years young.
Read more about it on: Reuters - Age of mother affects child's autism risk: study