By Gavin Mackintosh And Charlotte Webster-
Older parents, particularly fathers, are more likely to have children on the autism spectrum, according to longstanding research on the the topic.
The research supported by a series of studies spanning the past decade sheds light on the intricate relationship between parental age and the prevalence of autism
Numerous epidemiological studies have delved into the correlation between parental age and the likelihood of having a child with autism. The results consistently point towards an increased risk associated with older fathers.
Most members of the general public are unaware of the potential connection of older parents having children and autism, or higher intelligence.
This finding does not mean younger parents cannot produce higher intelligent or autistic children. Many times younger parents are themselves descendants of much older parents, either directly, or further up the genetic chain.
A seminal study in 2006, drawing on medical records of 132,000 Israeli adolescents, revealed that men in their 30s are 1.6 times more likely to have a child with autism than men under 30, with a staggering six fold increase for men in their 40s.
Subsequent analyses in California, Denmark, and Sweden, along with a global dataset encompassing 5.7 million children, have reinforced the link between paternal age and autism prevalence.
The odds of having a child with autism steadily rise over time, with varying results indicating increases ranging from 5 to 400 percent.
The chances become higher for fathers who become parents in their mid to late 40’s or higher.
Despite these increased odds, the absolute chance of having a child with autism remains is still not very high even for older parents, but has a higher probability than younger parents with no connection to an older parent (who is significantly over 30 years of age)
A 2017 study, based on whole-genome sequencing, suggests that parents in their mid-40s are 5 to 10 percent more likely to have a child with autism than 20-year-old parents.
However, researchers still examining the topic believe the chances of older parents having an autistic or generally more intelligent child become higher the more activity the parent has engaged in over the course of their life.
‘A very active 40 year old individual over the course of their life engaged in fitness, sports, violence or a lot of mental activity, is more likely to produce an autistic child than a 40 year old with less intense activity throughout their life”, one psychologist researching the autism and intelligence from the American psychologist Association anonymously told The Eye Of Media.Com
”In the same vein, if you find a highly educated 40 year old who has a child after several decades of intellectual development and mental activity, you will find a higher probability of such a child being super intelligent naturally, varying with the depth of the development of the parent, and sometimes the combined genes of both parents’
The prevailing hypothesis behind the higher odds in older fathers revolves around the accumulation of spontaneous mutations in sperm. Sperm cells undergo more divisions than egg cells, offering more opportunities for mutations.
Studies in Iceland have shown that de novo mutations accumulate more rapidly in men than in women, with an average increase of two mutations per year in men.
This theory is further substantiated by studies in mice, indicating that pups of older male mice harbor a relatively large number of mutations.
De novo mutations are changes in the gene sequence not inherited from parents. They are new mutations and have been absent in families in previous generations.
While de novo mutations account for around 20 percent of the increased odds, other factors may contribute. It’s conceivable that men who are likely to father a child with autism might have children later in life due to autism traits that affect their ability to find a partner.
Link Between Mother’s Age And Autism
The link between a mother’s age and autism risk is more intricate. Some studies suggest that women face increased odds of having a child with autism both when they are much older and much younger than average. The effects of maternal age, however, are not as straightforward as those observed in fathers.
Studies indicate that the chance of having a child with autism for women over 35 is lower than for younger women. The increase in de novo mutations in egg cells with age is less pronounced than in sperm.
Yet, intriguingly, women under 25 may face higher odds of having a child with autism, echoing findings that teenage mothers also exhibit increased autism prevalence, depending on their own genetic set up.
A 25 year old woman whose father had her when he was 45 and whose mother was 35 may become a carrier of the autistic gene even if she escapes it herself.
Such a woman may have inherited high intelligence due to the advance age of her parents when she was born, especially where the parent has been utilizing their brain
Older parents, despite the increased autism risk, may produce more intelligent children. The connection between advanced parental age and heightened intelligence in offspring has been a subject of scientific inquiry.
While investigating this connection, researchers have uncovered that the trend toward later parenthood only accounts for a modest percentage of the increase in autism prevalence.
The biological intricacies underlying both the increased risk of autism and the potential for enhanced intelligence in offspring remain subjects of ongoing investigation.
In a society that continually seeks to unravel the mysteries surrounding neurodevelopmental disorders, these findings highlight the need for nuanced conversations.
Understanding the complexities of the relationship between parental age and autism not only dispels misconceptions but also opens avenues for further research into the biological underpinnings of this multifaceted condition.