dr. terry bilhartz is 61 and professor of history at sam houston state university in huntsville, texas.r. bilhartz's discovery of low testosterone took place 11 years ago. >> it was, of course, the blood work that identified the low testosterone. i knew i wasn't in optimal health at age 50. i knew i was slightly overweight. i knew that my cholesterol levels were too high. i knew that my blood pressure was slightly higher than it should be. but nevertheless, grading myself on the curve, i felt that i was healthy. >> mcfarland: unlike many hypgonadism patients, dr. bilhartz experienced no noticeable symptoms of this condition. >> very interestingly, not all patients become symptomatic, and that's an area of research. we do not know why. >> well, the basic question is, what can i do about it? and the answers i've received, i think, was a very wise answer, that there are really three steps to improvement. one is improved diet, and two is exercise, and then three is actually the hormone therapy itself. >> the treatment right now that's been approved by the fda is replacing testosterone, in d