Rise in Autism Cases Reported, 1992 - 2008

    Oops, it's happened again. As a science journalist, I am frequently embarrassed by the way important scientific ideas tranmogrify into gushy, silly, or scary notions in the media. The idea at stake this time could hardly be more important: it's that evolution plays a central role in many of the pathologies we experience. This idea was explored in a Sackler symposium that became the basis for a news release.
    Now, here's how that release is playing out in the media: "While natural selection is best known for weeding out the weak, it may also be partly responsible for the apparent rise of some disorders, such as autism, autoimmune diseases and reproductive cancers, according to researchers." (MSNBC)
    "Pressures from evolution may explain the rise of autism, cancer and autoimmune disease. Researchers believe that taking a broader evolutionary perspective to health can reduce suffering and the risk of death." (Digital Journal)
    "The subtle but ongoing pressures of human evolution could explain the seeming rise of disorders such as autism, autoimmune diseases, and reproductive cancers, researchers write in the Proceedings of the National Academy of Sciences." (Science Daily)
    The common thread here is a claim in the lede that evolution can explain "the seeming rise" of this, that, or the other. Nonsense. Those rises have been recorded in a matter of decades, not to say years. Unless you believe in LaMarck, there is no way in the world the chart of autism cases shown above can be explained by natural selection. Even with teen pregnancy booming, there is simply no time here for evolution to do its thing.
    What is actually going on with the explosion of autism, allergy, and cancer cases is more probably a rise in diagnoses (or overdiagnoses), combined with the unmasking of some diseases that would not have had the chance to emerge in earlier times, because something else would have killed the poor sod first. Cancer is a prime example. When you double the life expectancy of people by suppressing infectious disesase (as we did in the 20th century), you have to expect far more cancer cases.
     This does not mean that evolutionary medicine is bunk. On the contrary, along with genomics and proteomics, it is the future of authentic medicine. From what I can glean from the National Academies of Science page on the Sackler symposium, no one was proposing that evolution explains the *rise* in diagnoses of autism, cancer, asthma, etc.

     There may well be plausible evolutionary explanations for the  prevalence of these conditions in relation to our ancestors or primate relatives, but they can't explain what we've seen in recent decades. With the exception  of microbial evolution, the timescales are simply out of whack.  

 
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