Penn ethicist challenges Michele Bachmann

Presidential aspirant Michele Bachmann has a reputation for being gaffe-prone, but her latest comments so incensed University of Pennsylvania bioethicist Arthur Caplan that he has challenged her to put her money where her mouth is.

Bachmann told Fox News and the Today Show earlier this week that she had heard from a distraught mother whose daughter "suffered mental retardation" as a result of receiving the Gardasil cervical cancer vaccine.

Caplan used Twitter and email to announce that he would donate $10,000 to the charity of Bachmann's choice "if she can produce a case in one week... verified by three medical experts that she and I pick of a woman who became 'retarded' (her words) due to the vaccine."

"She must donate 10K to a charity I pick if she fails to do so," Caplan added.

He was inspired by a colleague.

Steven Miles, a bioethicist at the University of Minnesota School of Medicine - where Caplan used to be his boss - on Tuesday used Facebook to offer $1,000 for "a properly signed medical release" verifying Bachmann's anecdote.

"He upped the ante, so obviously he's doing well," Miles quipped.

On Thursday, Bachmann's press secretary Alice Stewart said she had not seen any reward offer and so couldn't comment.

Stewart said the Bachmann's vaccine comments, made Monday during a debate with GOP presidential candidates, were aimed at Rick Perry. As Texas governer, Perry signed an executive order - later overturned by the legislature - manadating that 12-year-old girls receive the vaccine, which protects against the virus that causes cervical cancer.

"The point she was making was the fact that Gov. Perry exceeded his executive privilege. He bypassed the legislative process," Stewart said.