Abstract: The fertility of females, especially human females can be predicted by use of a clomiphene challenge test. The test is based upon comparison of follicle stimulating hormone and/or luteinizing hormone levels in urine or blood samples at two points in the menstrual cycle. The first test is performed on days 2-3 of the cycle. Clomiphene, and most preferably clomiphene in the form of clomiphene citrate, in a dosage of about 100 mg/day, is then administered, preferably on days 5-9. The second test is conducted on days 9-10. The test results are most conveniently compared by colorimetric methods involving monoclonal antibody reactions with follicle stimulating hormone and/or luteininizing hormone.