Parkinson's disease is caused by a lack of the chemical dopamine in the brain and results from both genetic and environmental factors. Symptoms include rigidity, fatigue, trembling, slow movement, small handwriting, loss of thoughts, and remaining still for long periods. Treatment includes dopamine agonists and physical therapy to maintain strength and mobility. Michael J. Fox, famous actor diagnosed with Parkinson's in 1998, now advocates for research through his foundation to advance study of potential treatments like embryonic stem cells.