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.     
Dr. J. L. Capelo obtained his degree in Chemistry by the University of Santiago de Compostela in 1994 and his . in Chemistry in 2002 by the Vigo University, Spain, where he was assistant to staff (grant) from 1994 to 1997 and from 1998 to 1999; and associated professor (Lecturer) from 1999 to 2002. He was honored with the University of Vigo’s award to the best Doctoral Thesis defended in 2002 in the Faculty of Chemistry. In February 2002, he moved to IST, Technical University of Lisbon, as a postdoctoral researcher. In December 2004, he became Research Fellow at REQUIMTE (), at the Chemistry Department of the New University of Lisbon, and in 2006 he was invited as senior lecturer in the same institution. Begging 2009 Dr. Capelo moved as Research Fellow to the University of Vigo, Physical Chemistry Department (Spain). Since 2012 Dr. Capelo is located as Assistant Professor at the Department of Chemistry, Faculdade de Ciências e Tecnologia, REQUIMTE - Universidade Nova de Lisboa (FCT-UNL), Moonte de Caparica, Portugal.