Many medications cause alterations in all categories of male infertility. Cimetidine, now an over-the-counter heartburn medication, suppresses the hypothalamic-pituitary-gonadal (HPG) axis in a reversible manner. Genitourinary infections in the male are an uncommon but potentially treatable source of infertility. Chlamydia trachomatis has long been studied as a putative disrupter of male fertility. Clomiphene citrate has been used since the early 1990s to stimulate spermatogenesis in the man with nonobstructive azoospermia. Kallmann syndrome is a rare subset of hypogonadotropic hypogonadism (HH) associated with other midline defects including anosmia. Another endocrine disorder, hyperprolactinemia, is also responsible for male infertility. Prolactin inhibits luteinizing hormone (LH) action on Leydig cells. Although the incidence of a prolactin-secreting pituitary adenoma is low, it is the most common functional pituitary tumor. Macroadenomas have warranted a referral to a neurosurgeon for transphenoidal or, more recently, endoscopic removal.