NEWSWEEK took on the anti-vaccine debate this week by profiling Paul Offit, a vaccination doctor whose new book, "Autism's False Prophets," challenges the notion that vaccines cause autism. Offit's critics left hundreds of comments on our Website asserting that vaccination isn't safe and urging NEWSWEEK to re-investigate. You can't prove a negative in science, but you could show this is an issue readers certainly care about.

But after many posts insisted that vaccinations lead to autism, others fought back: "I am trying to understand the anti-vaccine argument," writes one reader. "If vaccines cause autism, how come all children who have their regularly scheduled vaccines do not have autism? Both my children had their regularly scheduled vaccines. My son was also a participant of the retrovirus study. They have not been diagnosed with autism. Are we allto believe that this was caused by vaccines? How do you explain children who were autistic before vaccines were readily available. I think parents are looking for something to blame, which is a common reaction." Others took this one step further, calling it "irresponsible" to refuse to vaccinate children, even calling it bad parenting:

"Bottom line -- if you want a child, then you have to be aware of everything than can go wrong (i.e., autism, etc.) and be prepared for the consequences of your choice. Don't issue a blanket statement on vaccines, or anything else, without proof positive of cause and effect. It's irresponsible parenting to waste time blaming something, when that energy could be used to get treatment/therapies for the actual problem. However, it's much easier to blame. If pharmacotherapy is to blame for these illnesses, then the industry could be sued to gain money to "care for" all affected parties. You want kids? Know the risks, be prepared to accept them, and provide financially for the any care necessary."

Among readers who reported having autistic children of their own, their sentiment was a bit gentler: "As I read the comments I am amazed the venom of some comments," writes one mother. "My son is 22 years old and was diagnosed at 2 years of age. At that time, autism was an unknown disease. I struggled on my own trying to figure out what to do. I could not tell you if it was the shots or not... I would rather have my son like he is than risk him dying from a preventable disease. Every parent must read, research and make a educational choice about whether to give their child the shots or not."

Even those who contributed first-hand to our coverage of autism this week wanted to weigh in. To go along with the story, NEWSWEEK's video team produced a series of segments that included Offit, families on both sides of the issue and lawyers like Robert Krakow who represent families of kids who feel vaccinations made their children autistic. After reading our story and discovering that we focused on Offit, he emailed us his final take:

"Although my interview was captioned, 'At Odds With Offit' I was asked but one question about him or his views: “What do you think about Dr. Offit?” I was not asked to address Dr. Offit’s assertions about the science underpinning our claims. I was, revealingly, asked specifically about “threats” by parents – a side issue that has been pressed by Dr. Offit that I did address, but without reference to Dr. Offit’s remarks on this subject. I do not believe that the issue of “threats” by parents is a major concern nor do I feel that this subject warrants focus by journalists, unless the purpose is to unfairly demonize parents as irrational or dangerous.

...My comments were meant to emphasize the legitimacy and credibility of parents' observations. There exists substantial scientific evidence that corroborates and amplifies parents’ first person accounts of what happened to our children."