There have been a lot of mixed martial arts fighters of late that are acknowledging their usage of testosterone replacement therapy (TRT). The latest is Dan Henderson who has been using it since 2007 (
http://espn.go.com/blog/MMA/post/_/id/2991/hendo-trt-user-since-2007-speaks-on-use). Nate Marquardt was recently pulled from a main event the day before when his levels were too high as a result of TRT (he had previously had 3 fights under TRT). Chael Sonnen also claims he was undergoing TRT when he failed his test after the Anderson Silva title fight and was suspended by the commission.
It got me to thinking on whether or not this is prevalent in other sports and what your thoughts on it are. I mean should you be allowed to utilize testosterone in this manner and still be a professional athlete. It seems like it could be abused fairly easily (or unintentionally abused as Marquardt alleges), but with regular testing levels can be monitored. This isn't all that difficult for one off events like fights, but would be difficult to monitor for an everyday sport like baseball.
Testosterone can be low in males for any number of reasons and the likelihood increases greatly as one ages. The sport aspect also has the added concern because one of the main ways a person can develop low testosterone is by steroid abuse.