The goals of this research proposal are to further our understanding of the reproductive aging process in women and to improve our ability to clinically assess and model reproductive aging. Reproductive aging is a continuous process that begins many years prior to menopause. Women in their late 30s and early 40s usually maintain normal menstrual function and ovulatory status, yet fertility in these women is considerably compromised compared to younger women. The primary mechanism of reproductive aging is through the process of ovarian primordial follicle (egg) depletion, a process that exhibits considerable variation between women. As a result, the age at which an individual begins to experience infertility and menstrual cycle changes secondary to follicle depletion also varies significantly and is difficult to predict. Multiple studies have investigated the impact of lifestyle choices (tobacco use, oral contraceptives, BMI, alcohol use, and parity) on reproductive lifespan by correlating the impact of these exposures with the age of spontaneous menopause. Although occasionally in agreement, many of these studies report contradictory findings. Alcohol use either delays or has no effect upon the age of spontaneous menopause. Similarly, oral contraceptive pill use has been suggested to both accelerate and delay the onset of menopause. The most consistent findings regarding the impact of these factors is an acceleration in the age of menopause by 1-2 years in smokers. Given the lack of consistent findings in these investigations, the exact impact of lifestyle factors on reproductive age is currently unknown. Nevertheless, the magnitude of such exposures in the U.S. population is considerable, with 19% of adult women using oral contraceptives and 19.2% current smokers according to recent statistics. This proposal seeks to develop better models of normal female reproductive aging through anatomical studies investigating the impact of lifestyle choices on ovarian primordial follicle number. A secondary aim is to determine the relationship between newly described markers developed to assess biological aging in other organ systems (white blood cell telomere length and the measurement of advanced glycation end products (AGEs) through skin autofluorescence) and reproductive age.