The purpose of this study is to look at how a chemotherapy treatment (Temozolomide, also called Temodar) affects the process of ovarian aging which is measured by a decline in ovarian follicle count, in patients with Low Grade Glioma (LGG). It is important to know if different patient factors and Temozolomide influence the rate of ovarian aging in women with LGG who have good long-term survival rates. This will allow better counseling about the effects of this particular chemotherapy agent on fertility in women.