Testosterone is a hormone produced in the male testes. During a boy's pubescent years (ages 9 to 14), there is an increase in production that leads to male secondary sexual characteristics such as a deeper voice, more muscle mass, facial hair growth and enlargement of the Adam's apple (among others). Some teenage boys experience these puberty changes at later ages than others. The timing of puberty is often genetically determined (through heredity), but other factors can play a role in delaying it, such as poor nutrition, physical trauma and certain diseases. Stimulating testosterone production naturally is possible in teen boys, although in rare cases hormone therapy may be needed to trigger and complete puberty.
Eggs often come up in reproductive health discussion. This time we’re talking about dietary eggs, as in omelettes, and the role they play in boosting testosterone. The hormone boost from eggs comes primarily from the yolks, which are rich in dietary cholesterol, mono- and saturated fats—nutrients once demonized by health experts that have since proven to positively influence waistlines and hormone-health. In fact, studies on vegetarian and low-fat diets both show reduced testosterone levels of about 12 percent. Where higher fat diets of at least 40 percent of calories, with a higher intake of saturated fat, show increased testosterone levels. Why? It’s not rocket science. After all, cholesterol makes up the building blocks from which testosterone is formed; without it, the hormone simply can’t synthesize. Organic eggs are one of the best dietary sources. In addition to essential fatty acids, a whole egg is rich in aspartic acid, an amino acid that triggers production of testosterone.
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.