This chapter examines the evidence for fetal exposure to environmental contaminants. It analyses the description of a unifying hypothesis for the inter-relatedness of adverse male reproductive health outcomes. The chapter focuses on the human data generated to date on the relationship between adulthood exposures to environmental chemicals and male reproductive health. The agents discussed in the chapter include phthalates, pesticides, organochlorines, solvents, and metals based on their exposure prevalence and the presence of existing human data. Male subfertility appears usually as impaired semen quality. Sperm number, motility, and morphology can be affected. Men with a history of cryptorchidism or hypospadias tend to have poor semen quality and suffer from infertility more often than other men. Cryptorchidism is a well-known risk factor for testicular cancer. Endocrine disrupters with antiandrogenic properties prevent normal masculinization of male fetuses, and androgenic compounds can masculinize female fetuses.