Michael J. Fox talks about Parkinson’s cure and stem cell research (VIDEO)

Michael J. Fox, a long time proponent of stem cell research as a possible key to finding the cure for Parkinson's disease, said there have been "problems along the way," in an interview with ABC's Diane Sawyer.

"Stem cells are an avenue of research that we’ve pursued and continue to pursue but it’s part of a broad portfolio of things that we look at. There have been some issues with stem cells, some problems along the way," said Fox.

He continued, "It’s not so much that [stem cell research has] diminished in its prospects for breakthroughs as much as it’s the other avenues of research have grown and multiplied and become as much or more promising. So, an answer may come from stem cell research but it’s more than likely to come from another area."

Fox said he still believes strongly in stem cell research and government support for those studies. He said that for Parkinson's the cure may come from drug therapies, experimental surgeries and earlier diagnosis, according to ABC News.

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Parkinson's is a brain disorder which manifests itself in shaking and difficulty with walking and coordination, according to the National Institutes of Health. It can also cause anxiety, confusion, depression and memory loss.

According to The Los Angeles Times, an estimated 0.4 percent of people in industrialized countries suffer from Parkinson's, affecting 1 percent of those over the age of 60 and 4 percent of those over 80.

In April, the French pharmaceutical company Sanofi said it would collaborate with the Michael J. Fox Foundation to test an experimental drug treatment for Parkinson's disease, according to Reuters.

The collaboration would entail the foundation sponsoring a phase I clinical trial of the drug AVE8112, which has shown promise as a therapy for the psychiatric symptoms of the disease, said Reuters. Patient enrollment will begin later this year in the US.

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Here is a segment of the interview, courtesy of ABC News: