Endometrial stem cells injected into the brains of mice with a laboratory-induced form of Parkinson's disease appeared to take over the functioning of brain cells eradicated by the disease. The finding raises the possibility that women with Parkinson's disease could serve as their own stem cell donors. Similarly, because endometrial stem cells are readily available and easy to collect, banks of endometrial stem cells could be stored for men and women with Parkinson's disease