A massive new autism study adds to the evidence that parents' age plays a role in their children's risk of autism—including the suggestion that a couple with a big age gap has a higher risk. "Though we've seen research on autism and parental age before, this study is like no other," the study's co-author says in a post at Eureka Alert. Scientists studied the medical records of nearly 6 million kids across five countries (not including the US) and found that paternal age had the greatest influence on autism risk. A child born to a dad over 50 had a 66% higher risk of autism than one born to a dad in his 20s. A child born to a man in his 40s had a 28% higher risk. Men over 50 may have genetic mutations in their sperm that play a role in autism development, though other factors are probably involved, reports HealthDay.
However, a mom's age also was a factor, perhaps due to genetic mutations in eggs. The autism risk in children born to a mom in her 40s jumped 15%. When both parents were older, the risk climbed again. Interestingly, the autism risk also spiked if a mother was especially young. The children of teen moms saw an 18% increased risk compared to those of women in their 20s, which researchers weren't able to explain, per Medical Daily. The study also is the first to link increased autism risk to an age gap among parents. The risk of autism in this group was highest when dads were between 35 and 44 or moms were in their 30s and their partners were at least 10 years their junior. That's another subject that needs more study. Researchers stressed they don't want to stress people. "Although risk for autism may increase when parents are older or have a gap in ages, most of the children born to such couples will [not develop autism]," says one. (A special-ed teacher got suspended for hugging an autistic student.)