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Scientists: Autism develops due to environmental influences
Medical expert of the article
Last reviewed: 30.06.2025
Research by scientists from Stanford University (USA) suggests that in most cases the causes of autism spectrum disorders are not genetic, but can be attributed to environmental influences.
It has become extremely popular in recent times to attribute the cause of autism to faulty genes (the fact that there are hundreds and hundreds of such genes does not seem to bother anyone). This hypothesis is supported by the obvious hereditary nature of this mental disorder: according to estimates, in 90% of cases, autism is transmitted along with genes. However, the results of a study presented by a group of scientists from Stanford University in the journal Archives of General Psychiatry indicate the opposite: in most cases, autism can arise due to non-genetic factors - for example, the age of the parents, the conditions of fetal maturation during pregnancy, etc.
Scientists observed families with twins born between 1987 and 2004, at least one of whom had autism spectrum disorders. In 77% of cases, both twins developed autism, which is not surprising, since they carry an identical set of genes. According to the researchers, differences from the “genetic” hypothesis began when they turned their attention to fraternal twins, whose genetic sets are no more similar to each other than those of normal children born at different times. In such twins, the level of coincidence was 31%. At the same time, in previous studies that took into account fraternal twins, it was claimed that the probability of autism in both babies was almost zero.
These data force us to take a new look at the role of the environment in the development of autism spectrum disorders. Overall, the authors estimate the influence of genetic factors in the development of classic autism and other autistic disorders (say, Asperger syndrome) at 37-38%. Consequently, they “blame” the environment in 55-58% of cases.
Supporters of the genetic origin of autism could not ignore these "outrageous" data. The main complaint addressed to the authors was that they were looking where the light was; in other words, the researchers mainly dealt only with families where both twins were autistic. There may not have been malicious intent in this: couples who had suffered twice from this incomprehensible disorder could more easily establish contact with scientists. Critics of the work, also recalling the times when parents were blamed for everything (their coldness and carelessness, they say, led to autistic disorders), say that it is important not to allow the resuscitation of such a point of view, which was so difficult to shake through the efforts of psychologists and geneticists.
On the other hand, we are now seeing the opposite picture, when every sneeze is attributed to the action of some gene, and genetic influence is used to explain everything from political views to love of classical literature. In general, it is high time to recall the well-known scientific cliche that states that “this issue requires further study.”
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