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.     
This is a wonderfully detailed and informative post. I have been reading about the possible side affects of raw maca, and that it should be consumed in the cooked/gelatinized version only. Do you have any thought on this? I have been using a blend from Navitas in my pea protein shake that has maca root in it. I have more energy and the chest breakout (no acne in my family, and never had it as a teenager) I started to get after 30 has gone. I feel leaner and lost 6 pounds in the last 2 weeks too. I should point out that I have also cut out dairy,grains, processed sugar/products, and am using erythritol (sugar alcohol) instead of equal now. I am not entirely sure if the breakout was hormonal, or an allergic reaction to something else that developed in my 30s. I will continue to use maca though, particularly since I am now in my early 40s, and I feel much better. I ordered the gelatinized maca, and camu camu from amazon (Navitas). The price ($21) is so much less than Whole Foods ($60 for 16oz).