At the heart of the male reproductive physical examination is investigation of the scrotum and its contents. The scrotum itself may be hypoplastic on one or both sides, suggesting lack of contents since birth. This chapter describes the basics of interpreting semen analysis in the context of a man's initial evaluation presenting with concerns about fertility, or a couple who has not conceived within a reasonable period of time. Sperm motility may be difficult to assess, and is often inaccurately reported by labs infrequently performing semen analyses whose technicians may be unfamiliar with the appearance of sperm under the microscope. Sperm morphology can be one of the most frustrating parameters of semen analysis. Sperm shape is highly variable, and a normal man's ejaculate contains a broad assortment of strange-looking sperm. Excessive aromatase activity resulting in abundant estradiol may interfere with the male endocrine axis and sperm production.