The Reproductive Riff on Paternal Age
Thought you might like to know about this. While preparing for my speech to the American Urological Association next month on the risks of being an older dad, I came across this pretty compelling research relating a father’s age to autism in children.
Name the fastest growing serious developmental disorder in the U.S. Correct, it’s autism. It is now estimated to affect 1/68 U.S. children. As a group of brain development disorders, autism and autism spectrum disorders are diagnosed in early childhood and characterized by repetitive behaviors and difficulties with social interaction and verbal and nonverbal interaction. In the words of John Robison: “Autism is a communication disorder, with a broad range of affect. Some people’s autism makes them eccentric and geeky. Other people can’t speak at all…”
No one really knows why autism occurs or what causes it. Having said this, there are more theories to explain it than there are cars in rush hour traffic: genetics, epigenetics, fetal and post-fetal environments, autoimmune disease, heavy metal exposure, vaccines and viruses to name a few.
A Real Story
But, what has grabbed my attention recently is the fact that there is a real story taking shape that links autism to paternal age. Suggestions of such an association were made in the 1970s, but more rigorous and systematic population-based research within in the last decade has cast a much brighter light on this intriguing relationship.
The most recent study to address this link hails from Sweden. Imagine examining the entire population of Swede’s born between 1973 and 2010 (2,615,081 individuals!) to study the link between offspring with autism and dad’s age at their conception. Well, in a veritable monument of informatics research, this is exactly what was done. And after the dust settled, they found that compared with offspring born to fathers 20-24 years old, offspring of fathers >45 years old were 3.5 times more likely to develop autism. That’s some real risk here. Not sure? Compare it to the fact that smokers have a 2-fold increased risk of heart attacks compared to non-smokers and you might agree.
A True Story?
But there is even more to the story. I believe that in this world, universal truth is revealed to us in small dollops, often announced and frequently missed, like a light Spring rain. Is this such a moment? I say this because it is rare in medicine that two schools of thought agree: in this case, molecular biology and population science. If you recall, I recently highlighted a genetics study that, by taking an entirely different approach to the problem, also showed a significant relationship between older dads and kids with autism. And the key to this study? The finding that new mutations in offspring came mainly from dads and not moms. And how might these little genetic mutations be getting from dad to kids? SPERM, my friends.
Maybe that’s why Dan Crane involved me when deciding whether or not to bank sperm as “older” single guy; even to investigative mind, the truth is often hard to come by.
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