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.     
Clinical studies of DELATESTRYL did not include sufficient numbers of subjects, aged 65 and older, to determine whether they respond differently from younger subjects. Testosterone replacement is not indicated in geriatric patients who have age-related hypogonadism only (“andropause”), because there is insufficient safety and efficacy information to support such use. Current studies do not assess whether testosterone use increases risks of prostate cancer , prostate hyperplasia , and cardiovascular disease in the geriatric population.
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