Is there empirical evidence that parental age is a contributing factor to giving birth to a child with autism?
“Got Questions?” is a new weekly feature on our blog to address the desire for scientific understanding in our community. We received over 3000 responses when we asked what science questions were on your mind. We answered a few here and the Autism Speaks Science staff will address the other themes we received in this weekly post.
A number of recent publications investigating the relationship between parental age and autism have demonstrated that older parents are at increased risk for having a child with autism. This is not surprising since increased parental age is associated with a slightly increased risk for other developmental disorders, as well. Grether, et. al. reported in 2009 that parental age and particularly maternal age is a significant risk factor for autism. The authors found that a 10-year increase in maternal age increased the chances of having a child with autism by 38% and mothers over the age of 40 were at highest risk. Other studies, such as a recent study by Hertz-Piccioto, found that the risk for autism spectrum disorder (ASD) in older mothers was lower than 38%. King and Bearman, et. al. similarly found that older mothers and fathers were at increased risk of having a child with autism with the largest risk among mothers aged 40 and over. Since the risk for ASD is low, the risk for ASD in older mothers, although increased, is still relatively low. The underlying mechanism behind the relationship between increased parental age and risk for autism is currently unknown and under investigation.