Image: Dan Saelinger
In Brief
- Silicon Valley and other tech-savvy communities report exceptionally high rates of autism. These trends might reflect a link between genes that contribute to autism and genes behind technical aptitude.
- When two technical-minded individuals pair up, their children may inherit genes for useful cognitive skills, as well as genes involved in the development of autism.
- Furthermore, high levels of testosterone in the womb may play a role in the development of both technical and autistic minds.
More In This Article
In 1997 my colleague Sally Wheelwright and I conducted a study involving nearly 2,000 families in the U.K. We included about half these families because they had at least one child with autism, a developmental condition in which individuals have difficulty communicating and interacting with others and display obsessive behaviors. The other families had children with a diagnosis of Tourette's syndrome, Down syndrome or language delays but not autism. We asked parents in each family a simple question: What was their job? Many mothers had not worked outside the home, so we could not use their data, but the results from fathers were intriguing: 12.5 percent of fathers of children with autism were engineers, compared with only 5 percent of fathers of children without autism.
Likewise, 21.2 percent of grandfathers of children with autism had been engineers, compared with only 2.5 percent of grandfathers of children without autism. The pattern appeared on both sides of the family. Women who had a child with autism were more likely to have a father who had been an engineer—and they were more likely to have married someone whose father had been an engineer.
Coincidence? I think not.
A possible explanation involves a phenomenon known as assortative mating, which usually means “like pairs with like.” I first encountered the concept in an undergraduate statistics tutorial at the University of Oxford in 1978, when my tutor told me (perhaps to make statistics a little more lively) that whom you have sex with is not random. When I asked her to elaborate, she gave me the example of height: tall people tend to mate with tall people, and short people tend to mate with short people. Height is not the only characteristic that consciously and subconsciously influences partner selection—age is another example, as are personality types. Now, more than 30 years later, my colleagues and I are testing whether assortative mating explains why autism persists in the general population. When people with technical minds—such as engineers, scientists, computer programmers and mathematicians—marry other technical-minded individuals, or their sons and daughters do, do they pass down linked groups of genes that not only endow their progeny with useful cognitive talents but also increase their children's chances of developing autism?
System Check
I began studying autism in the 1980s. By then, the psychogenic theory of autism—which argued that emotionally disinterested mothers caused their children's autism—had been soundly refuted. Michael Rutter, now at King's College London, and others had begun to study autism in twins and had shown that autism was highly heritable. Genetics, not parenting, was at work.
Today researchers know that an identical twin of someone with autism is around 70 times more likely to develop autism, too, compared with an unrelated individual. Although researchers have uncovered associations between specific genes and autism, no one has identified a group of genes that reliably predicts who will develop the condition. The genetics of autism are far more complex than that. What I have been interested in understanding, however, is how genes for autism survive in the first place. After all, autism limits one's abilities to read others' emotions and to form relationships, which in turn may reduce one's chances of having children and passing on one's genes.
One possibility is that the genes responsible for autism persist, generation after generation, because they are co-inherited with genes underlying certain cognitive talents common to both people with autism and technical-minded people whom some might call geeks. In essence, some geeks may be carriers of genes for autism: in their own life, they do not demonstrate any signs of severe autism, but when they pair up and have kids, their children may get a double dose of autism genes and traits. In this way, assortative mating between technical-minded people might spread autism genes.
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12 Comments
Add CommentSimon Baron-Cohen suggests that assortative mating between geeks "might spread autism genes". But surely the opposite is true. He may be right to claim that that when geeks mate with other geeks their children are more likely to be autistic. However, as he himself points out, autistic individuals have lower reproductive fitness. So, this must mean that geeks who mate with other geeks are likely to have fewer grandchildren -- fewer, that is, than if they had mated with non-geeks and had children who were not autistic. The net result must be that assortative mating, even if it works to increase the incidence of autism, actually works to reduce the spread of genes for autism.
Reply | Report Abuse | Link to thisDid I overlook it, or was any mention of other factors beyond genes absent from this article?
Reply | Report Abuse | Link to thisIf this were purely a genetic disease, then it would have been with us throughout history. Genes do not change that fast, so there must be an environmental trigger. Since the first cases started appearing at the same time as vaccination, and increased with more vaccinations required, parents should be forgiven for thinking there is a connection. Health authorities have not found any other causes, and we keep being bombarded with this genetic message, which cannot be the only factor. No wonder parents are having to figure this out by themselves and do not trust health authorities, and people like this author.
It is time for the medical establishment to grow up and stop pretending that medical issues are black and white. Yes vaccination has saved lives, but we don't know the full consequences of this much monkeying with the immune system. So, how about a moratorium on genetic articles about autism? Someone needs to do better research on the subject and help parents who don't know how to avoid having their child join a lost generation of ruined lives.
"..having their child join a lost generation of ruined lives."
Reply | Report Abuse | Link to thisI am annoyed at this comment and I am sure I am not the only one. There's all kinds of wrong in that quote.
I only read the preview, but isn't the whole point of the article about the genetic gifts that Autistic people have that contribute to the advancement of the scientific (if not the entire)world?
I am a parent of a scientifically minded autistic child who has one parent an engineer, one a mathematicion and 4 grandparents that are scientists/engineers/doctors. I know my child will lead a rich and fulfilling life following in his ancestors footsteps.
His life is nowhere near ruined and he may even discover something that will earn him a Nobel Prize.
I believe it's the attitude that being autistic = a ruined life that may prevent these kids from getting the support they need in school to excel in their gifts.
Autism can be linked to reproductive success in the same way as the genes for sickle cell anemia, i e having one copy of the gene might increase fitness while having two copies decrease fitness. That way a "harmful" may survive in the population.
Reply | Report Abuse | Link to thisSince all types of autism and now Asperger's Syndrome are all lumped together by a recent revision to the psychiatric diagnosis guidebook as "Autism Spectrum Disorders", it's increasingly difficult to discuss what are often quite disparate conditions. As I understand, those with high functioning autism and Asperger's Syndrome are very similar in their abilities to function (but with distinct limitations) in society. However, many if not most with autism suffer debilitating disabilities and may not be able to care for themselves much less function in society.
Reply | Report Abuse | Link to thisI wholeheartedly agree that many "ASD" sufferers can, perhaps with greater obstacles to encounter and overcome, not only function but prosper in society and enjoy a very satisfying life. Moreover, as the author points out, many are very significant contributors to the general benefit of society.
Perhaps these beneficial attributes are what perpetuate "ASD" genes in the general population. One can even argue that, in modern technological society, the ability to systematically analyze complex conditions is so highly valued and significantly beneficial that the frequency of associated genes should be expected to increase in the future...
"Since the first cases started appearing at the same time as vaccination, and increased with more vaccinations required, parents should be forgiven for thinking there is a connection."
Reply | Report Abuse | Link to thisPerhaps uninformed parents can be forgiven for perpetuating the myth fostered on the victims of a now discredited physician in the past, but they should also consider that, if autism is a developmental condition and that vaccinations are often scheduled to coincide with conditions like the child's loss of immunities initially endowed by their mother's immune system, the two events could each be coincidentally related only to child development. As always, correlation does not infer causation.
Tentative hypothesis that seems to fit with other findings re: rates of autism and aspergers in less-developed societies. Perhaps parents who are overly concerned about early academic development that are partly responsible. Their emphasis on reading and other intellectual activities inhibits the "natural" progression of development where the child learns about its physical environment and develops skills and self-confidence in it. Related, spending a lot of time with adults who are exerting subtle pressure for the child to learn what the adult wants may also interfere with social play with other children where other basic skills and self-confidence usually develop.
Reply | Report Abuse | Link to thisI realize these conditions are complex and other factors play a part. Just interested in what others may think.
Why are we always so eager to use genetics to explain our differences? The article summary here has no mention of environment. What readily comes to my mind is that engineers are migrant workers. Specialty education forces people to relocate to specialty jobs. Any autism researcher should know the well-established link between change in familial location and autism incidence (diet as culprit). Not mentioned here at all. It should be considered first. The questions should have been asked: How far apart are the locations where these engineers grew up and where the now live, vs the non-engineers?
Reply | Report Abuse | Link to thisKlinefelter Syndrom (KS) is associated with autism risk and along with Down's Syndrome is the most common genetic sydrome associated with increased autism risk. KS is not inherited and is always caused by an extra X chromosome. Half the cases are caused by an XY sperm mutation and half the cases are caused by an XX egg mutation producing the KS XXY genotype. Interestingly, in contrast to Baron-Cohen's high testestorone theory, Klinefelter Sydrome is associated with a drop in testosterone production in the neonatal testosterone surge period.
Reply | Report Abuse | Link to thishttp://ghr.nlm.nih.gov/condition/klinefelter-syndrome
McCAuliffe's group recently discovered exposure to increasing levels of PCB and DDT congeners, as measured in blood, produced increase frequency of XY sperm in sub-fertile men.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3339457/pdf/ehp.1104017.pdf
I'm not sure where you got the bizarre idea that Autism didn't exist before vaccinations but your idea is wrong. Autism existed centuries, if not thousands of years before vaccinations, it just wasn't a formal diagnosis until the advent of modern medical knowledge. Perhaps if you bothered to do any real research you would realize just how moronic your post sounds. The term "Tuberculosis" is a recent label that replaced "consumption". Names change but that doesn't mean the disorder is new. How many Autistics were called changelings, slow, possessed, or other archaic terms that meant "not like the rest of us"?
Reply | Report Abuse | Link to this@tetrahedral
Reply | Report Abuse | Link to thisI can say about my child that very early, maybe 6 months (I forget but his mother remembers very well) when I (the primary care giver) went off to work in the evening, his mother had a difficult time consoling him when he cried.
Interestingly though, she noticed when the shopping channel was on, or when CNN news was on (with subtitles), he would stop crying. He wouldn't stop crying when his mother held him and those channels weren't on but he was comforted when his mother held him with her back to the TV.
By age 3 he was reading in two languages and reflecting back, we see that even at the earliest age, he had more interest/understanding in letters than in his mother's and actually anyone's words/touch.
I am a teacher but honestly was quite surprised when I realized at two that he was teaching himself to read. OK there were words on the pictures we looked at such as "gorilla", but my style is to talk about the card. Big gorilla, black gorilla, I want a banana (act like the gorilla and pretend to eat a banana).
Also, I did point at the words when I read a book, but again I talk more about the pictures than I do reading. And the reading was only rhyming books, but he did not acquire intonation in English until after mastering his second language. It was really weird where he picked up verbal intonation in his second language (age 6) much more easily and then started to develop it in his first.
Actually, we ended up at those activities because his ability and interest in verbal language was late to develop and because I could just tell what he was interested in. I just naturally chose the things that held his attention. Still, it is really very true to say that any neurologically typical child would end up talking about the pictures like their parent was instead of learning to read the words.
There is no doubt whatsoever that my child was neurologically predisposed to seek out the patterns in symbols as opposed to paying attention as other kids do to facial expressions, and tone of voice.
Reading to this day remains intrinsically rewarding to him in a way that verbal discussion does not.
It's all making sense to me now. As an architect who's been plagued with the forced reality of "collabarating" with engineer's for decades, I always suspected something was inherently wrong with most of these individuals. I always knew that one part of their brain was not activating properly: the sensing, empathising, spiritual, moral parts of the brain. They seem to be stuck on the left side of their brains...systemitizing...a true Mr.Spock. But, being their moral superior, I KNOW that I must aspire to coexist with these strange beings, therefore I do and repeatedly forgive them their many moral lapses and unimaginable cruelties, as lesser evolved beings. I guess we still need human calculators after all.
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