Ian Schlom's List: Burning Balls

Oh shit. This method, if used for extended periods of time may result in a lower sperm count. The test subject had a significant loss in the sperm count after using this method for 12 YEARS.
It's important to note though that he was using this method for 12 years. Now, I don't know how long I'll be using this method, but it seems that this method is good for the short-term, while the long-term is maybe not so safe an idea for eventually maybe having a child.
Apart from that little bit, this page is very well-informed, cites what they say, and is generally informative and brings a lot of light onto the issue. I need to get in touch with my doctor.

Qt: It is now clear that fertility may not return completely after long-term use of heat methods. After keeping meticulous records during more than 12 years of use of the special underwear method, one long-term user has found that his sperm count after quitting is only a fraction of what it was before. Keep in mind, if trying heat methods, that they may gradually impact fertility over time. Except for short-term use, heat methods should not be used as a reversible method- they should only be used by men who are okay with potentially being less fertile, or not fertile, in the future.

This is a neat little blog. It's general conclusion is that the test is successful, although the testing was not realiable and not done in a real lab setting. So I should keep searching for more info.