Life is full of changes and in the period of adolescence, changes begin to develop on what a person will be like as an adult. Many factors mature in adolescence, for example, one of them is sexuality. Sexuality can be a very important variable in the life of an adolescent, because it is during this period of life that sexual identity is defined. There are three strong circumstances that can define an adolescent's sexual identity: biological characteristic, love and pornography. Biological characteristics are an important fact for the development of sexual identity, a more precise definition of biological characteristics can be sex, according to Oxford Dictionary Sex means: "Either of the two main categories (male and feminine) in which humans and most other living things are divided on the basis of their reproductive functions. » (“Sex”, 2013) The definition of sex is linked to the idea of ​​genitals which define us as men or women. Therefore, sex is one of the main stimulants of sexuality, because man is formed by testosterone and estrogen, testosterone levels are higher than estrogen levels and this causes in man the most violent and masculine traits. On the other hand, girls have more levels of estrogen than testosterone, because estrogen is the one that generates body development in women (Gwartney, 2013). A good example to better explain the theory of biological characteristics is the case of Dr. Money and the boy without a penis, an experiment against biological rules; it's a BBC case and also a documentary, because it causes a lot of controversy. In 1965, when twins Brian and Bruce Reimer were sent to the local hospital for a routine checkup...... middle of paper ......t. Belomont: Wadsworth. Brown, J.D., Steele, J.R., & Walsh-Childers, K. (2002). SEXUAL ADOLESCENTS, SEXUAL MEDIA: Investigation into the influence of the media on adolescent sexuality. New Jersey: LAWRENCE ERLBAUM ASSOCIATES, PUBLISHERS. Hartel, CE, Zerbe, WJ and Ashkanasy, NM (2005). EMOTIONS INORGANIZATIONAL BEHAVIOR. New Jersey: Lawrence Erlbaum Associates. Schetky, DH and Benedek, EP (2002). Principles and practice of forensic child and adolescent psychiatry. London: American Psychiatric Publishing.Sex, (2013) Oxford English Dictionary online edition (http://www.oxforddictionaries.com/definition/english/sex).Gwartney, D. (2013). Predetermined effects on testosterone and estradiol. Tools, 13, 00.BBC. (2010). Dr. Money and the Boy Without a Penis [Video file]. Retrieved from http://www.youtube.com/watch?v=MUTcwqR4Q4Y&list=PL4XMCGEuCKGULWW_LekD2OU3TnLP3Loe1