Male Hormone Therapy Popular but Untested. We talk incessantly about evidence based medicine. Often we have no evidence.

"The only thing we ever learn from medical history is that we never learn," said Dr. John B. McKinlay of the New England Research Institutes in Watertown, Mass. Dr. McKinlay is the director of the Massachusetts Male Aging Study, a federally supported study that follows more than 1,700 men as they age. "On the slimmest of evidence we introduced estrogen to women," he said, "and the public was whipped up to ask for it."

Referring to the large clinical trial of hormone therapy in women that was halted last month, Dr. McKinlay added: "We ended up, finally, after everyone was getting it, with 45 million prescriptions in the U.S. each year. And suddenly we find that not only does it not do what it is supposed to do but there are these untoward consequences.

"We are about to repeat that debacle. We have the slimmest evidence on testosterone replacement. Five men here, 10 men there. Six rats and a partridge in a pear tree. The physiology is not there but the industry, the industry is there."

We have learned too many times that what seems like good logic may be wrong. When will we learn. Nothing replaces good, carefully collected data.