13-cis Retinoic Acid (Isotretinoin) and Sperm Production

Inclusion Criteria: * Subjects will be infertile men (no pregnancy with partner with normal cycles and normal hysterosalpingogram despite \>1 year of unprotected intercourse). * Abnormal sperm analyses with a total, motile sperm count of less than 10 million sperm as assessed by semen analysis on two occasions separated by one week. * Male patients aged 21-55 years * Affiliation with a social security system * Ability to provide informed consent Exclusion Criteria: * -Men participating in another clinical trial * Clinically significant abnormal findings at screening * Known genetic infertility (e.g. Klinefelter syndrome or Y-chromosome microdeletions), * Hypogonadotropic hypogonadism (that might respond to gonadotropin injections), * Severe mental health problems requiring medications * Current therapy with retinoic acid (e.g. Accutane) or vitamin A. * History of psychiatric disorders (e.g., depression, suicidal tendencies). * Abnormal serum chemistry values according to local laboratory normal values which indicate liver or kidney dysfunction. * Men currently receiving tetracycline containing medications * Men who have used isotretinoin within eight weeks of the start of dosing * Men with elevated serum triglycerides