This is my 113th and final Age of Autism column. United Press International, which has been the hospitable home for this series, is restructuring, and I'm off to adventures as yet unknown -- although I intend to keep my focus on autism and related issues.

Why? Because it is the story of a lifetime.

"Autism is currently, in our view, the most important and the fastest-evolving disorder in all of medical science and promises to remain so for the foreseeable future," says Dr. Jeffrey A. Lieberman, chairman of the department of psychiatry at Columbia University's school of medicine.

Most mainstream experts believe autism is a genetic disorder that's "increasing" only because of more sophisticated diagnoses. But based on my own reporting, I think autism is soaring due to environmental factors -- in the sense of something coming from the outside in -- and that genes play a mostly secondary role, perhaps creating a susceptibility to toxic exposures in certain children. As the saying goes: Genes load the gun, environment pulls the trigger.

So to me, the issues autism raises -- about the health and well-being of this and future generations, about the role that planetary pollution, chemical inventions and medical interventions may have inadvertently played in triggering it -- are so fundamental that by looking at autism, we're looking very deeply into the kind of world we want to inhabit and our children to inherit.

It is impossible to summarize all the issues I've raised in my columns, but to me, four stand out:

-- The first question I asked when I started looking at autism in late 2004 was this: What is the autism rate among never-vaccinated American children? Vaccines are the leading "environmental" suspect for many families of autistic children. So I was stunned to learn that such a study had never been done, given that it could quickly lay to rest concerns that public health authorities say are dangerously undermining confidence in childhood immunizations.

Rep. Carolyn Maloney, D-N.Y., introduced -- and just reintroduced -- a bill to force the Department of Health and Human Services to do just that (generously crediting this column for finding enough never-vaccinated children to show that such a study is indeed feasible). She calls it "common sense," and it is an example of ordinary people -- through their representatives -- telling the experts they want better answers, and fast.

Recently, such a study was in fact done with private funds. It was a $200,000 telephone survey commissioned by the advocacy group Generation Rescue that, as limited as it is scientifically, suggested a disturbing trend: Higher rates of autism in vaccinated vs. never-vaccinated U.S. children, along with similar ratios for other neurodevelopmental disorders like attention-deficit/hyperactivity disorder.

I reported the same possible association in the Amish community. That's been criticized as inherently unscientific and undercut by the fact that Amish genes may differ from the rest of us and that increasingly, the Amish do receive at least some vaccinations.

All true, but intriguing nonetheless. I also found a family medical practice in Chicago called Homefirst that has thousands of never-vaccinated children as patients. According to its medical director, Mayer Eisenstein, he's aware of only one case of autism and one case of asthma among those kids -- not the 1 in 150 and 1 in 10 that are the national averages for those disorders -- and he has the medical records to prove it.

I wrote about that in 2005, yet when I met again with Mayer in Chicago last week, he told me not one public health official or medical association has contacted him to express any interest. Nor has any other journalist -- not a one.

-- That brings me to my second theme. I am sorry to say my colleagues in the mainstream journalistic community have, in the main, done a lousy job covering this issue. They, of course, would disagree -- two were quoted (anonymously!) in the Columbia Journalism Review saying, "Olmsted has made up his mind on the question and is reporting the facts that support his conclusions."

Actually, my mind is made up about only one thing: Both vaccinations and autism are so important that definitive, independent research needs to be done yesterday -- and the fact that it hasn't should be making more journalists suspicious.

I think Big Media's performance on this issue is on a dismal par with its record leading up to the Iraq war, when for the most part it failed to probe deeply into the intelligence about weapons of mass destruction and the assertions about Saddam Hussein's link to al-Qaida. And it's bad for the same reasons -- excessive reliance on "authorities" with obvious conflicts of interest; uncritical enlistment in the "war on terror" and "the war on disease" without considering collateral damage or adverse events; a stenographic and superficial approach to covering the news, and an at-least-semiconscious fear of professional reprisal.

In the case of Iraq, that fear included being cut off -- like my exemplary fellow ex-Unipresser Helen Thomas -- from precious "inside sources" in the government; in the case of autism, fear of alienating advertisers lurks silently in the background.

To see how squeamish and slow-on-the-uptake the media can be in the face of an urgent health crisis, look no further than the early days of AIDS, as chronicled in Randy Shilts' "And the Band Played On."

-- Another angle I explored intensively involved a group of families in Olympia, Wash., who noticed their children regressing into autism after getting four live-virus vaccines -- mumps, measles, rubella (MMR) and chickenpox -- at an early age and in close temporal proximity. These cases seemed to have little or nothing to do with the mercury preservative in other vaccines, called thimerosal, that many parents blame for autism (it was phased out of most routine immunizations starting in 1999).

That raises an ominous prospect: The still-rising autism rate might be related to some other aspect of the immunization schedule as well -- timing, age, total load or other ingredients. (I didn't invent that idea; the head of an expert panel mandated by Congress expressed it to me in an interview -- and again, her comments were largely ignored.)

One focus of that seven-part Pox series last year was a case of autism following a small clinical trial of a new vaccine called ProQuad, which contains the live-but-weakened MMR and chickenpox viruses in one shot. The chickenpox virus in ProQuad is about 10 times the amount in the standalone chickenpox shot, a boost needed to overcome "interference" among the four viruses (and a possible sign of trouble right there). Manufacturer Merck says the vaccine is safe and not related to autism.

Earlier this year the company announced it was suspending production of ProQuad -- barely a year after its introduction -- because supplies of chickenpox vaccine had run unexpectedly low. The company, however, will keep producing its other products containing chickenpox virus: the standalone chickenpox shot and a new vaccine for shingles.

A Merck spokesman told me the suspension of ProQuad had nothing to do with any safety concerns, that it had been selling well and would be reintroduced as soon as chickenpox vaccine supplies were replenished. As I've written before, I found Merck to be quite accessible and forthcoming when I asked questions about this issue -- much more so than the Food and Drug Administration, in fact.

So I take Merck at its word. But -- in the spirit of trust-but-verify -- I'll be watching for the return of ProQuad.

-- The Age of Autism columns that may mean the most over time (IMHO, of course) are about the first cases of autism, reported in 1943 at Johns Hopkins University in Baltimore among 11 children born in the United States in the 1930s.

With crucial observations from Mark Blaxill of the advocacy group SafeMinds, I've suggested a pattern in some of those early cases: exposure, through the father's occupation, to ethyl mercury in fungicides. That's the same kind of mercury used in vaccines, and both were introduced commercially around 1930, right when those first autism cases were identified.

This is only a hypothesis, and critics have suggested it is a classic case not of connecting the dots, but of finding what I went looking for. That may be, but put yourself in my place when -- more than a year after publicly proposing the mercury fungicide idea in a column -- I identified the family of autism's Case 2 and located an extensive archive for the father, a distinguished scientist.

I sat down in the North Carolina State University library and opened the first box, took out the first folder and opened it to the first page. It was a yellowed, typewritten paper from spring 1922 summarizing a fungicide experiment the father conducted as a grad student in plant pathology -- an experiment in which mercury was the main ingredient (and in the title). By the time his son was born in 1936, he was working with the new generation of ethyl mercury fungicides -- yes, the kind used in vaccines.

Though others will disagree, I find that just a bit outside the parameters of chance, given the timeline of the disorder and the independent belief of so many of today's parents that the same kind of mercury, in a totally different context, triggered their children's autism.

It also suggests that whatever is causing autism could be coming at us from several directions -- our increasingly mercury-toxic environment as well as any medical interventions that may be implicated. Check out "Mercury Link to Case 2" in the series to get the full picture.

So thanks to UPI for supporting this work. And thanks for reading, responding to -- and critiquing -- this column. Truth is, you haven't heard the last word from me. Not by a long shot.

(The entire Age of Autism series is available at upi.com under Special Reports.)

(e-mail: olmsted.dan@gmail.com)