Many of the factors involved in sterility are still unknown, but, when married couples desire children, diagnostic surveys are frequently successful. Careful diagnosis is essential to good treatment, but for some reason pregnancy sometimes follows the diagnostic survey before treatment is begun. Attention must be given to both partners. Each must have a physical examination, and laboratory procedures such as semen analysis may be necessary in addition to special procedures such as tubal patency tests and culdoscopy. The diagnosis, though sometimes difficult, occasionally reveals a situation that is obviously remediable by medicine or operation. The roles played by various hormones in pregnancy tests, in the induction of ovulation, in controlling spermproduction, and in preventing fetal wastage need to be better understood and more fully utilized.