Testosterone is my favourite hormone, a focus of my research. In the public mind it is the body s most potent chemical, making the diference between a 90-pound weakling and a he-man, between a milquetoast and a lothario. Steroid analogues, stacked by muscle builders, are supposed to cause out-of-control roid rages . Some people - lieve an injection of testosterone propelled Floyd Landis from also-ran to his mirac- lous Stage 17 of the Tour de France. The hormone has become part of the language of popular cultureT . he New York Times carried the following passages in the previous 2 weeks: I...

Infertility is defned as the inability to conceive after having unprotected intercourse for a year. Infertility is increasing worldwide and has various causes both in the male and the female partner. Immune reactions to sperm can contribute up to 2 30% of infertility. The sperm has both autoantigenic as well as isoantigenic potential, and is thus capable of p- ducing antisperm antibodies (ASAs) and sperm-reactive T cells in both infertile men and women. Also, over 75% vasectomized men produce autoantibodies to sperm that can cause a problem in regaining fertility even after successful...