This is a big subject, but let me just give a few highlights:
--Part of it is a carrover from concerns about prostate cancer. It is a fact that anti-androgens seem to help prostate cancer and some research indicates that existing prostate cancer is fueled by testosterone. Right now almost of all those concerns have been allayed from a variety of studies. Talk to your doctor, of courrse, about his understanding, but basically once a few big studies showed no increased prostate cancer risk for men on HRT, Big Pharma got involved and are now pushing Androgel and soon Testim. Plus, many other products came out as well and HRT clinics and so on. This is why things are changing now. However, many doctors still have the concerns about prostate cancer on the back of their mind. And who knows? Maybe some subpopulations will be found to have issues in the future? None of us has a crystal ball...
--An association with steroid use. Guess who uses testosterone cypionate? Many men on HRT. Guess who else uses testosterone cypionate? Steroid users. Many doctors still associate HRT with steroids. Basically, the docs feel like men are just trying to get testosterone to get a unneeded boost of confidence in the bedroom or even to build some muscle. Of course, that's because it's not THEM with low testosterone. If they were hypogonadal, they'd be crying like a schoolgirl and self-injection by sunup.
--Incorrect protocols. Some of the doctors have not had stellar success. Why? Because they prescribe Androgel and that has common absorbency issues. Or because they gave injections every two weeks such that men have estrogen spikes and four days of low testosterone end of cycle. These kind of mistakes can lead docs to believe that HRT is of debatable value. I know that HRT clinics will tell you that they have a very high success rate because they 1) go for the 600-900 range and 2) manage estradiol. NOTE: Not all men will respond to testosterone treatment. The reason, of course, is that they have other root causes, usually endothelial.