ABC’s Michael Falcone, Amy Walter and Arlette Saenz report:

RICHMOND, Va. — On Wednesday Rick Perry dismissed rival Michele Bachmann’s claim that the vaccine he sought to make mandatory for young women in Texas causes mental retardation.

“I think that was a statement,” Perry said, that has “no truth and no basis in fact.”

In 2007 Governor Perry signed an executive order requiring all sixth-grade girls in Texas to receive the vaccine Gardasil, which prevents the HPV virus, a trigger for cervical cancer. The order was later overturned by the Texas state legislature before the mandate went into effect.

At Monday night’s presidential debate in Tampa, Bachmann sharply criticized Perry for endangering the lives of “innocent little 12-year-old girls.” She went even further in an interview on Tuesday.

“I had a mother last night come up to me here in Tampa, Florida, after the debate,” Bachmann said on NBC’s “Today Show.”  ”She told me that her little daughter took that vaccine, that injection, and she suffered from mental retardation thereafter.”

Speaking to reporters after an appearance at a Virginia Republican Party fundraiser here on Wednesday, Perry defended his HPV decision.

“I hate cancer and that’s what this has always been about for me. I made a mistake in the way that I took this forward,” he said. “But nothing’s changed in my life from the standpoint of giving people the opportunity to conquer a disease that is impacting so many people in our country.”

Perry said that his mother and father are both cancer survivors and he recalled sitting at the bedside of a young woman as she was dying from cervical cancer. The woman he was referring to was Heather Burcham, who Perry said was an inspiration for his 2007 executive order. Burcham died from her cancer at the age of 31 the same year of his executive order, and Perry spoke at her memorial service. (Burchman was featured as an ABC News “Person of the Week” just months before her death.)

On Wednesday Perry said he “readily admitted” he should have handled things differently in Texas.

“We should have had an opt-in instead of an opt-out,” he said. “But, at the end of the day, I am always going to be erring on the side of life.”