The weight of the roles of environmental factors versus genetic factors in the cause of autism has frequently shifted. A study is now suggesting that environmental factors may play a larger role than was previously thought.
The study published in the journal Archives of General Psychiatry, reports that scientists at Stanford University identified 192 pairs of twins in which at least one of the two had some form of autism. Among these sets, there were 54 pairs of identical and 138 pairs of fraternal twins. The researchers then examined the children for autism themselves. What they found was that the genes twins share can increase the risk of getting autism by about 38%, but the environment twins share in the womb and immediately after birth may increase the risk even more – an estimated 58%.
Dr. Joachim Hallmayer, “A California Population-Based Twin Study of Autism,” study’s lead author said that the study shows a “need to accept that we have to go down the route of environment and genetics,” when it comes to studying the causes of autism, “we have to look at both sides of coin.”
Autism becomes apparent by the time a child turns 3 and begins to show significant social, communication and behavioral difficulties. Historically, neglectful parenting was thought to be the cause of ASDs. Later in the century, scientists gave more weight to genetics when it was found that several specific genes are linked to autism.
Recently, scientists have been saying that there has to be something else triggering autism in genetically susceptible children. Hallmayer says, “We’re finally moving to a little bit of a middle position and we have to really study both factors.” His study adds more weight to the argument that both aspects are key to understanding autism.