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.     
As with almost any Testosterone variant or derivative, Testosterone Cypionate cycles tend to almost always be utilized for the purpose of bulking, mass gaining, and strength gaining periods of training. Though its ideal use is for this purpose, this is not to say that it cannot be used effectively (albeit at a lower dosage) for cutting cycles where fat loss is the primary goal. For the purpose of bulking and/or gaining mass and strength, Testosterone Cypionate is usually employed at a higher dosage (approximately 500mg/week). It is usually utilized at this dosage for a period of 12 – 14 weeks due to its longer ester, and therefore longer half-life. Testosterone Cypionate possesses a half-life of around 10 – 12 days. By comparison, its close counterpart Testosterone Enanthate is almost the same, with a half-life of around 7 – 10 days.
Transdermal patches (adhesive patches placed on the skin) may also be used to deliver a steady dose through the skin and into the bloodstream. Testosterone-containing creams and gels that are applied daily to the skin are also available, but absorption is inefficient (roughly 10%, varying between individuals) and these treatments tend to be more expensive. Individuals who are especially physically active and/or bathe often may not be good candidates, since the medication can be washed off and may take up to six hours to be fully absorbed. There is also the risk that an intimate partner or child may come in contact with the application site and inadvertently dose himself or herself; children and women are highly sensitive to testosterone and can suffer unintended masculinization and health effects, even from small doses. Injection is the most common method used by individuals administering AAS for non-medical purposes.