Women between 18 and 50 years of age who are in good health may be eligible for this study. Premenopausal women must not be pregnant (as determined by a urine pregnancy test) or breastfeeding and must practice birth control during the study. Candidates will be screened with a medical history, physical examination, and blood and urine tests. Women who use an IUD for contraception are advised to also use a barrier contraceptive (diaphragm or condom) the week after taking CDB-2914.