Michael J. Fox On His Battle With Parkinson's: 'Like Having A 4-Year-Old Climbing On You'

Oprah Winfrey and Michael J. FoxGeorge Burns, Harpo ProductionsAccess Hollywood

CHICAGO, Illinois -- Despite Michael J. Fox 's ongoing battle with Parkinson's disease, the actor says it's just one part of his life - and usually one that acts like a rowdy child stuck inside of him.

"It's like having a 4-year-old climbing on you all the time," the 47-year-old actor told Oprah on an episode of her talk show airing Tuesday. "And, so whatever you're trying to do, you've got this 4-year-old and you're... just trying to be patient and focus on what you need to do."

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Nevertheless, Fox told Oprah he doesn't allow his life to be ruled by the disease.

"I'm a dad, I'm a husband, I'm an activist, I'm a writer and I'm just a student of the world," he says. "This is one fact of my life, but it's not the totality of my life. It doesn't define me."

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Fox also applauded President Barack Obama's executive order overturning the ban on federal funding for research involving human embryonic stem cells earlier this month.

"It was absolutely crucial that this research be unfettered and allow us to go forward in a responsible way," he told Oprah, recalling the day he heard the ban had been overturned. "It's an exciting day."

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