Robert:

Indeed the most persuasive theory currently out there is that the move to use of live, attenuated viruses in modern vaccines, away from the previous use of dead viruses in older vaccines, is ultimately responsible, as the insufficiently attenuated live viruses proliferate and overwhelm some persons' immune systems.

This "theory" is hardly persuasive for many reasons, not the least of which is that the underlying premise is flatly false. The notion that "modern" vaccines use live, attenuated viruses and "older" vaccines use dead viruses is just plain silly, and those of us who remember what we were taught in high school biology know it. The first successful smallpox vaccine ever developed (and still the only FDA-approved vaccine to protect against it) was the use of a live, attenuated version of the Vaccinia virus, which confers a cross-immunity to smallpox. This was developed in 1796 (NOT 1976!) by Edward Jenner. This was about 75 years before Louis Pasteur developed a vaccine against anthrax, which also was a live, attenuated vaccine.

Truly modern vaccines are neither live nor killed, but instead use recombinant DNA technology to produce protein molecules, and those proteins then elicit an immune response that is protective against the original target virus. The recently developed vaccines against certain strains of the Human Papilloma Virus family (HPV--the viruses that cause genital warts and cervical cancer) are good examples.

The conjecture that live, attenuated vaccines are the cause of autism may seem persuasive to you, but you have no evidence to back it up. The large number of studies done so far have found no link between MMR or any other vaccine and autism. Instead of prolonged explications full of conjecture and anecdotal evidence, please provide us with actual studies (peer-reviewed journals only, please) that show that your conjecture has any validity. Right now, your groundless statements seem to be the ones more appropriately called "irresponsible opinion-mongering".

In my opinion, the scientific community has gone to and continues to go to great lengths to ensure that the vaccines we give children are safe. The burden is on the naysayers and vaccine opponents to prove otherwise.