A Mayo Clinic study makes that claim in the March 19 online issue of Movement Disorders.
Genetics may play a greater role for women, while environmental factors such as exposure to pesticides, industrial chemicals and head injuries may play a greater role in whether men develop Parkinson's disease, the study says.
Using a two-step statistical analysis to study the risk factors for Parkinson's disease, the researchers found complex interactions between gene variants lead to an increased risk of the disease in women.
However, environmental exposures are often sufficient to increase the risk of Parkinson's disease in men, the researchers suggest.
The researchers did genetic tests on blood samples from 319 unrelated Parkinson's disease cases and 196 cases with no evidence of the disease. The blood samples came from people taking part in ongoing Mayo Clinic studies examining the causes of Parkinson's disease.
The researchers are doing more studies to test their theory that genetic factors play a more significant role in women while environmental factors are more significant in men.
It's been known for years that more men than women develop Parkinson's disease, but the reasons for that have been unclear.
Here's where you can learn more about Parkinson's disease.