CNN

Watch John Roberts' interview with Mitt Romney.

WASHINGTON (CNN) - GOP presidential hopeful Mitt Romney defended his conversion on abortion rights in an interview with CNN over the weekend, less than a week after Sen. John McCain's presidential campaign sharply questioned the former Massachusetts governor's stance on the issue.

"You know, as governor, all the decisions I made as governor and all the bills that came to my desk were - I came down on the side of life," Romney told CNN's John Roberts. "So when I ran for office, I was effectively pro-choice. I didn't call myself pro-choice, but I said I would keep the law the way it was. But the first time as governor that I saw a piece of legislation that dealt with life, I came down on the side of life."

Asked if some voters may be confused with his abortion rights record, Romney suggested people would understand that he had “learned from experience.”

"You know, if you've never changed your mind on anything, if you've never felt that at some point you learned from experience, and as a result you had changed your mind, if someone's never done that, well, they probably don't understand how it happens," he said.

On Wednesday, the McCain campaign posted a YouTube video from a May 2005 press conference in which then-Gov. Romney said he was "committed" to maintaining abortion rights in the state. The campaign argued the video indicates Romney supported abortion rights in 2005 even though he has said he changed his mind on the issue in 2004.

Romney’s camp fired back, saying “selective editing” had taken the Massachusetts Republican’s comments out of context and called the video’s posting “borne of desperation.”

– CNN Ticker Producer Alexander Mooney