Causes of autism remain the subject of debate until today. There are various theories as to how autism came about. Some of the controversy also center on whether or not there has been a marked rise in the cases of autism in the past 10 years.

Genetic Causes Of Autism
Some studies suggest that autism is caused by genes. These studies are supported by the finding that cases of autism in the general population is approximately 1.5 in 1000 people, but parents with an autistic child have a 1 in 20 chance of having another autistic child.

Many neurobiologists also say that autism is the most heritable of all the neurobiological conditions. This belief is based on research done in twins. Twin studies are able to help establish a genetic link for a condition by noting the difference in prevalence of the condition in identical (monozygotic) and fraternal (dizygotic) twins. If a condition is genetic in origin, the prevalence will be markedly higher in monozygotic twins, since they share the exact same chromosomes. In most twin studies conducted for autism, the prevalence of autism is as much as 90% higher in monozygotic twins than in dizygotic twins.

The studies themselves are subject to controversy, however. The fact that not one of the studies showed 100% concordance in monozygotic twins suggests that there could be other factors at play in the cause of autism. Other familial studies have noted common characteristics – for instance, that autism is more common in families of physicists and engineers. This observation gave rise to the term ‘the geek syndrome’ to identify autism.

Environmental Causes Of Autism
There are also many researchers who believe that environment factors are causes to autism. In 1967, Dr. Bernard Rimland suggested that autism was caused by mercury and heavy metal toxicity to which some children have a genetic sensitivity. He recommended treating autistic children with a gluten-free, casein-free diet and mercury chelation therapy (removal of mercury from the system). His treatment has since shown measurable success with some children.

Other environmental factors that can possibly play an important role in causing autism include viral or bacterial infections, vaccines and thalidomide.

The Supermale Brain Theory
One recent interesting theory is that autism is caused by high levels of testosterone during development in the mother’s womb. A study done in England measured the testosterone level of the amniotic fluid in mothers and then followed up with testing of children after birth and at four years. The study found that the babies with the highest levels of testosterone pre-birth had a smaller vocabulary and made eye contact less often at a year old, and were less socially developed at age four.

The conclusion made by the study is that high testosterone levels in the brain support the development of ‘male skills’ like analysis of systems and seeing patterns, but repress the development of ‘female skills’ like communication and empathy. Autistic children tend lack in the ‘female skills’.

For whatever the reason is in what causes autism, know that autism is not a psychological disorder. Researchers have long dispelled the myth that an autistic child is caused by the lack of a nurturing mother. Hence, do not blame yourself that you have been a bad parent and that have caused your child’s brain disorder condition. That is far from the truth!

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