Psychologist Simon Baron-Cohen of the Cambridge University Autism Research Centre has reiterated his previously stated position that autism results from the interaction of genetic AND environmental factors. In an exchange with a parent published on the One Click Group site Professor Baron-Cohen stated:
The One-Click Group seems to be a website for those who want to see more research into environmental risk factors in autism, and to me this seems to be a very worthy agenda. We know that autism is not 100% genetic in origin, since in the case of identical twins (who share 100% of their genes), there are instances of one twin having autism and the other not having it. In fact, the likelihood of the co-twin also having autism where one of them has it (in monozygotic (MZ) pairs) is about 60%. This means that there must be some non-genetic (i.e., environmental) factors that are part of the cause of autism. ...... I hope the above statement shows clearly and unambiguously that I regard autism as most likely the result of a gene-environment interaction.
Professor Baron-Cohen made the same point in a December 2007 interview piece published on TimesOnLine, Freedom of Expression:
Studies of twins have established that it is not 100 per cent genetic, since even among identical twins, when one has autism, the likelihood of both twins having autism is only about 60 per cent. This means there must also be an environmental component, but what it is remains unknown.
Professor Baron-Cohen's logic appears unimpeachable. Perhaps someone could convey the Professor's views to the US Department of Health and Human Services Interagency Autism Coordinating Committee (IACC) which decided to reverse its own recent decision to authorize funding research of potential environmental causes of autism, including vaccines. While they are at it perhaps they could also convey Professor Baron-Cohen's reasoning to the bloggers at the new ASAN media center at autism.change.org where they believe, as an article of faith, that autism is genetic.