Does Dad’s Age Play a Key Role in Autism Outcome?

Like women, more men are waiting until later in life to have children. Could this have an effect on the number of genetic mutations found in their children? A recent Icelandic study says, “Yes.”

Man Carrying Baby Drawing Their Foreheads

Published in the journal, Nature, the genetic study took a look at the number of genetic mutations found in the DNA of 78 parents and their children. After sequencing all of the families, researchers found a direct correlation between the number of slight DNA alterations or modifications in children and the age of their fathers.

“Society has been very focused on the age of the mother,” said the lead author of the study, Dr. Kari Stefansson of Decode Genetics. “But apart from [Down’s Syndrome], it seems that disorders such as schizophrenia and autism are influenced by the age of the father and not the mother.”

The study suggests that, for every year a man waits to have a child, two additional genetic mutations are passed along. Researchers estimated that the average 20-year-old father passes along about 25 mutations; the average 40-year-old father passes along around 65.

Researchers are uncertain as to how these additional mutations will affect a child’s overall health, but they theorize that it slightly increases the risk for certain neurological disorders.

This theory is based on former studies and the fact that the brain is most likely to be affected by mutations since it depends more on genes for development and regulation than any other organ in the body. Stefansson also cited that both the average age of men having children and the number of children diagnosed with autism has increased over the years.

“The average age of fathers has been steeply rising [in industrialized countries] since 1970. Over the same period, there has been an increase in autism and it is very likely that part of that rise is accounted for by the increased age of the father,” he said.

This is, of course, still just a theory, but experts are suggesting that men consider saving their sperm earlier in life if they plan on waiting to have a family.

“Collecting the sperm of young adult men and cold storing it for later use could be a wise individual decision,” said Professor Alexey Kondrashov of the University of Michigan, who was not involved in the study. “It might also be a valuable for public health, as such action could reduce the deterioration of the gene pool of human populations.”

Dr. Stefansson has a bit of a different take on the mutations; he believes they may actually speed up the evolution of the human species.

“The high rate of mutations is dangerous for the next generation, but is generating diversity from which nature can select and further refine this product we call man,” Stefansson said. “So what is bad for the next generation may be good for our species in general.”

Despite the warnings, however, Autism Speaks, one of the largest non-profit organizations for autism says there’s little cause for alarm at this point. They say there isn’t enough evidence to suggest a public health concern.

“While there is evidence to suggest that genetic factors may play a role in some forms of autism, there are many ‘younger’ fathers who have children with the condition,” a spokesperson for the organization said. “Far more investigation needs to be done in the connection between genetics and autism before we can draw any reliable conclusions.”

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Photo by Josh Willink

About the author


Kate Givans is a wife and a mother of five—four sons (one with autism) and a daughter. She’s an advocate for breastfeeding, women’s rights, against domestic violence, and equality for all. When not writing—be it creating her next romance novel or here on Growing Your Baby—Kate can be found discussing humanitarian issues, animal rights, eco-awareness, food, parenting, and her favorite books and shows on Twitter or Facebook. Laundry is the bane of her existence, but armed with a cup of coffee, she sometimes she gets it done.

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