If there’s anything Michael J. Fox would want his fans to know, it’s this: Having Parkinson’s disease has been an opportunity that’s opened up his life.

“I think that people who focus on the fact that I have this condition might be surprised by how happy I am, how productive I am, how much enthusiasm I have for life,” he told TODAY’s entertainment correspondent, Maria Menounos, in a taped interview that aired on Monday.

“It's one of those things that it happened to have created an opportunity for me to do things that I might not otherwise have done and put the rest of my life in relief,” he said.

The disease itself, which attacks the central nervous system, isn’t fun, Fox readily acknowledges, but people living with Parkinson’s could have it worse.

“Yes,” he said, “this is a drag to have this, but put it against everything else, it's like a pin in a haystack.”

Fox was diagnosed with Parkinson’s in 1991 at the age of 30 and made his condition public in 1998. Two years later, the star of the “Back to the Future” trilogy and the hit TV shows “Family Ties” and “Spin City” retired from full-time acting.

Since then, he’s been very active politically in campaigning for candidates who support embryonic stem-cell research that many feel holds the best hope of finding a cure for Parkinson’s and other central-nervous system diseases.

The Bush administration, along with pro-lifers and many fundamentalist Christian groups, has opposed the use of embryonic stem cells because, they say, human embryos have to be destroyed to harvest them.

Proponents of the research point out that the embryos used are in the very earliest stages of development, before cells begin to differentiate, and would be discarded anyway.

Fox sat down with Menounos to talk about a recent breakthrough in which scientists were able to reprogram ordinary cells to behave like embryonic stem cells.

“Any of these breakthroughs are fantastic, and this was thrilling,” he said. “At the same time, we don't want to discontinue the embryonic stem-cell research that's being done, because one begets the other, and it's all part of a broad canvas that we want to continue working on.”

During last year’s congressional elections, Fox actively campaigned for candidates based on their stand on stem cell research, earning the wrath of Rush Limbaugh, who made fun of Fox’s condition.

Menounos asked him if he will be involved in the 2008 presidential and congressional elections.

“Just about everyone's in favor of it, with a couple of exceptions on the Republican side,” he said. “But what I did in the last elections, midterms, was not about parties, but about who was in a race where they supported stem cell research and were opposed by someone who was not in favor.”

Has he picked a candidate in the presidential race?

“I haven't,” he said. “I mean, whoever the most pro-science candidate that comes out of either primary.”

An accomplished musician — that really was him playing “Johnny B. Goode” in “Back to the Future” — the Canadian-born actor continues to play the guitar and spends his time with his wife since 1988, Tracy Pollan, and his four children: Samuel Michael, 18, twins Aquinnah Kathleen and Schuyler Frances, 12, and Esme Annabelle, 6.

Fox has, he told Menounos, “so many blessings and so much good stuff in my life. I have this idiot grin on my face all the time.”

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