Tip for politicians: before you repeat a story you might want to find out, from a credible source, whether it’s actually true.

It all started when some woman came up to Michele Bachman after the Republican presidential debate in which Bachman had criticized Rick Perry over a failed attempt to make the HPV vaccine mandatory for girls in the sixth grade. The woman is crying and tells Bachman that her (the woman’s) daughter got the HPV vaccine and “suffered mental retardation as a result of that vaccine,” Bachman said.

Yahoo News, among other sources, reported yesterday that, “pressed by Fox News' Sean Hannity on his radio program about the story, Bachman said she had ‘no idea’ if it were true.”

Another Yahoo! story quoted Dr. Evan Siegfried, spokesman for the Global and Regional Asperger Syndrome Partnership, as telling Politico, “There is zero credible scientific evidence that vaccines cause mental retardation or autism,” and "She should cease trying to foment fear in order to advance her political agenda.”

Bioethics professor Steven Miles offered $1k for proof that the vaccine caused the woman’s condition and his former boss, Art Kaplan, director of the University of Pennsylvania Center for Bioethics saw his $1k and raised it to $10k.

“These types of messages in this climate have the capacity to do enormous public health harm,” Miles said.

We have absolutely no proof of this but you know what’s may well be another cause of mental retardation, for both viewer and participant? Political campaigning.