Fertility and the physician.

Gonadal function in both sexes is under the synergistic control of the pituitary gonadotrophins, follicle stimulating hormone (FSH) and luteinising hormone (LH) which are in turn influenced both by the hypothalamus (via the gonadotrophin releasing hormone) and by feedback signals from the gonads. There is good evidence that such feedback is mediated by steroid hormones and by a product of the germinal epithelium, termed inhibin. A logical approach to reproductive disorders involves the localization of the primary disturbance either to the hypothalamo-pituitary unit or to the gonad, on the basis of history, physical findings and the results of hormone assays. In men, the majority of disorders leading to infertility are of unknown aetiology and cannot, therefore, be treated specifically. In women, anovulation is usually readily treatable and recent studies have emphasised the usefulness of prolactin assays and of specific treatment for hyperprolactinaemia in restoring ferility. Increased understanding of the mechanisms leading to infertility may provide valuable new approaches to fertility control.