I’d bet that watching sports decreases a man’s T over the long term. We see guys getting really amped up at games and in front of the television, yelling and so forth. Sometimes, a fight breaks out. There seems to be an increase in T, or at least aggression. But such things are momentary. What are the long term effects? The very act of watching another man compete is beta behavior. Really, the spectator might as well be a cheerleader. There must be a signal to the spectator’s brain that the athlete, whom he is watching, is bigger, faster, stronger, and, in the case of professional sports, richer. Also, the athlete probably beds more women. A game is basically a three-hour promotion to the spectator that he is a beta male. And the more exposure, the deeper the conditioning. We all know what the hook is: When the spectator’s team wins, he feels that he himself has won. Winning boosts T. So the spectator feels a rush. He’s happy, invigorated. But the victory is vicariously-lived. For that reason it is short-lived. So the spectator craves more. And more. And more. Before long, he’s a raging idiot who dresses up in costumes, the so-called 12th man. And when “his team” loses, well, it’s just an utter catastrophe, a complete emotional collapse with the attendant spectrum of rage and shame. I think watching sports is like a drug. Its boosts T for a short period of time by tricking the brain. The long term effects however are very unhealthy. Not only is it complete brain-cuck, it leads to a passive, sedentary lifestyle of overeating and excessive drinking, thereby further lowering T.
Testosterone is significantly correlated with aggression and competitive behaviour and is directly facilitated by the latter. There are two theories on the role of testosterone in aggression and competition.  The first one is the challenge hypothesis which states that testosterone would increase during puberty thus facilitating reproductive and competitive behaviour which would include aggression.  Thus it is the challenge of competition among males of the species that facilitates aggression and violence.  Studies conducted have found direct correlation between testosterone and dominance especially among the most violent criminals in prison who had the highest testosterone levels.  The same research also found fathers (those outside competitive environments) had the lowest testosterone levels compared to other males. 
Hey Richard – curious about your thoughts on carbs driving down testosterone. Do you have any studies to that end? I wonder whether the Kitavans had/have low testosterone, despite 70% carb intake? It doesn’t seem immediately obvious to me that carb intake alone would inhibit testosterone, as long as you were getting adequate cholesterol, fat-soluble vitamins, zinc, selenium, etc. to support testosterone levels. These nutrients are often severely lacking in modern diets, as I’m sure you know! So it seems like misplacing causation for correlation to say that modern diets lower testosterone BECAUSE of their high carb levels. (They also have low mineral density, low fat-soluble vitamin levels, low fiber, low polyphenols/antioxidants, high iron, high fluoride/bromide, etc., which all could be confounding factors in the carbs-lower-testosterone hypothesis.)