I’m just shy of age 71. I’ve always had a high sex drive, still do. I’ve only had two T tests, three years ago, 260, recently, 290. I don’t know if that was normal variation, or due to progesterone cream applications over the last few years. My Medicare insurer turned down a prescription the urologist wanted for Androgel. To help with weight loss. Despite those T numbers, I’m still randy as hell, and despite my alcohol consumption, my balls are still huge per internet sources. And many lovers over the years. (The urologist didn’t say anything was wrong.) The other morning I woke up with wood, walked out to the patio, and urinated a strong stream with a dick curving heavenward.
The second theory is similar and is known as "evolutionary neuroandrogenic (ENA) theory of male aggression".   Testosterone and other androgens have evolved to masculinize a brain in order to be competitive even to the point of risking harm to the person and others. By doing so, individuals with masculinized brains as a result of pre-natal and adult life testosterone and androgens enhance their resource acquiring abilities in order to survive, attract and copulate with mates as much as possible.  The masculinization of the brain is not just mediated by testosterone levels at the adult stage, but also testosterone exposure in the womb as a fetus. Higher pre-natal testosterone indicated by a low digit ratio as well as adult testosterone levels increased risk of fouls or aggression among male players in a soccer game.  Studies have also found higher pre-natal testosterone or lower digit ratio to be correlated with higher aggression in males.