This is a 3-year study. The total number of subjects enrolled will depend on the results obtained. The subjects will be at least 18 years of age and pre-menopausal. Exclusion to include pregnant women, and all subjects are told not to get pregnant while on study. Also, they cannot take hormones by mouth or patch while on study. The study can include healthy subjects as well. Blood will be drawn (120 ml) four times a year, randomly.