It has been known for a relatively long time that Parkinson's disease is associated with increasing motor neuron deficits, leading to the onset of Parkinson's symptoms. As current treatments for Parkinson's disease are not fully satisfactory, scientists are constantly seeking new therapeutic options to improve the prognosis of people with Parkinson's disease. One such method has been reported by scientists in the United States - it appears that female sex hormones may have a beneficial effect on the condition.