Michael Kinsley

A columnist for Time magazine and former editor of Slate, he's written frequently about living with Parkinson's and the political and ethical controversies surrounding stem cell research.

Charles Krauthammer

A syndicated columnist for the Washington Post and a Time magazine essayist, he suffers from a spinal cord injury and has written about the ethical issues surrounding embryonic stem cell research.

Dr. William Langston

Founder and scientific director of the non-profit The Parkinson's Institute, he has been studying Parkinson's for 25 years.