In August 2012, we pointed out an Icelandic study that found older dads are more likely to have autistic kids. New research now says that the older a man is when he conceives his child, the more likely it is that autism will show up in his grandchildren.
Because we know you want to have to think about multiple generations while piping out the baby batter.
The news comes from the JAMA Psychiatry (formerly Archives of General Psychiatry, if you were wondering where that one went). The study was performed by Emma M. Frans (and like 10 other people) at King’s College London’s Institute of Psychiatry, Karolinska Institutet in Sweden and the Queensland Brain Institute in Australia, and was carried out using the Swedish National Registers. Researchers took data reaching back to 1932 to identify 5,936 individuals with autism, and 30,923 without. Researchers had access to age and well-being data on the grandfathers and grandmothers of the study subjects.
What was found was “a statistically significant monotonic association…between advancing grandpaternal age at the time of birth of the parent and risk of autism in grandchildren,” says the study. Also:
Men who had fathered a daughter when they were 50 years or older were 1.79 times (95% CI, 1.35-2.37; P < .001) more likely to have a grandchild with autism, and men who had fathered a son when they were 50 years or older were 1.67 times (95% CI, 1.35-2.37; P < .001) more likely to have a grandchild with autism, compared with men who had fathered children when they were 20 to 24 years old, after controlling for birth year and sex of the child, age of the spouse, family history of psychiatric disorders, highest family educational level, and residential county.
Lead researcher Emma Frans admits to reading 8BitDad for this sort of thing: “We know from previous studies that older paternal age is a risk factor for autism,” she said, totally implying with hand gestures that 8BitDad was her source. “This study goes beyond that and suggests that older grandpaternal age is also a risk factor for autism, suggesting that risk factors for autism can build up through generations.”
Another researcher, Abraham Reichenberg, PhD, admits that this news shouldn’t necessarily stop men from fathering children because while the risk is “increased,” it’s also small. “However, the findings are important in understanding the complex way in which autism develops,” Reichenberg noted.