Numerous theories have been put forth regarding autism causes, but the fact of the matter is that even in this advanced day and age, no one really knows for sure what causes the condition.

While the most common explanation has been that autism is caused by a combination of many different factors–both genetic and environmental–the fact remains that there is very little certainty about what these particular factors are.

This lack of any solid knowledge has understandably led to a great deal of frustration for many people, particularly parents who either suspect that their child is afflicted with the condition or who already know for sure that their child is in fact autistic.

One bright light in the midst of all this uncertainty is that with strong worldwide media coverage of the condition, more and more funding is being channeled into finding autism causes and more thorough information is expected in the next few years.

One of the most controversial theories regarding the possible cause of this condition is that it is somehow related to commonly prescribed vaccines. Two particular vaccine-related practices have been called into question, one being the administering of the Mumps-Measles-Rubella or MMR vaccine, and the other, the use of the mercury-based preservative called thimerosal, which is found in many types of vaccines.

The MMR vaccine involves the introduction of three different sets of viruses into children at an age when autism has been commonly known to surface. Some feel that the combined shock of three viruses to the immune system is sufficient to cause the onset of autism.

While the link between MMR and autism is inconclusive as of the present, parents are now given the option to spread out the vaccination over 3 separate shots over several months.

As for thimerosal, the ingredient was widely used in many types of vaccines from the late 80s until 2003, and a corresponding rise in the number of autism cases has led to suspicions that there may be a connection.

As with MMR however, this connection remains inconclusive but thimerosal is nevertheless no longer widely used in vaccines.

Immune deficiency, food allergies and atypical brain development have also been proposed as possible autism causes.