The search for a reversible male contraceptive has centered upon the suppression of sperm production or sperm motility. Gossypol, a natural substance extracted from the cotton plant, appears to cause both of these effects. Its ability to reduce spermatogenesis in men is undeniable and has been demonstrated in both large studies in China and a smaller confirmatory study in Brazil. These investiga tions have revealed the remarkable fact that with gossypol, it is possible to separate an effect on the testis' gamete-producing function from an effect on its hormone-producing function. Thus, it is...

This volume is devoted to the chemistry, immunology, molecular biology, and physiology of the human chorionic gonadotropin, heG. For this glycoprotein molecule the course from discovery to chemical deciphering covered about fifty years. It was in 1928 that Ascheim and Zondek reported that urine from pregnant women contains something that stimulates the ovaries of mice or rats. This provided the basis for the famous A-Z test for pregnancy and for the "rabbit test" modification introduced by Friedman. As researchers sought to find more sensitive responses to heG, they used a wide variety of...

This volume contains papers presented at the Conference on the Demographic and Programmatic Consequences of Contraceptive In novations, which was sponsored by the Committee on Population and held at the National Academy of Sciences, October 6-7, 1988. The papers consider how new contraceptive methods currently being developed and changes in the use of already available contraceptives could affect contraceptive practice, levels and patterns of abortion use, and the health of women. In addition, several of the papers re view the probable consequences of introducing new technology into family...