Life is full of changes and in the period of adolescence the changes begin to develop into what a person will be in adulthood. 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 in this period of life sexual identity is defined. There are three strong circumstances that can define a teenager's sexual identity: biological characteristic, love and pornography. Biological characteristics are an important fact about the development of sexual identity, a more accurate definition of biological characteristics may be sex, according to in the Oxford dictionary sex means: “One of the two main categories (male and female) in which human beings and most other living things are divided on the basis of their reproductive functions.” (“Sex,” 2013) The definition of sex is connected to the idea of ​​genital organs that define us as male or female. Therefore sex is one of the main stimulators of sexuality, since the male is made up of testosterone and estrogen, testosterone levels are higher than estrogen levels and this causes more violent and masculine traits in the male. On the other hand, girls have higher levels of estrogen than testosterone, because estrogen is what 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; this is a case of the BBC and also of a documentary, because it raises a lot of controversy. In the year 1965, when twins Brian and Bruce Reimer were sent to the local hospital for a routine check-up c......middle of paper......t. Belomont: Wadsworth.Brown, J.D., Steele, J.R., & Walsh-Childers, K. (2002). SEXUAL TEENAGERS, SEXUAL MEDIA: Investigating the media's influence on adolescent sexuality. New Jersey: LAWRENCE ERLBAUM ASSOCIATES, PUBLISHERS.Hartel, C.E., Zerbe, W.J., & Ashkanasy, N.M. (2005). EMOTIONS INORGANIZATIONAL BEHAVIOUR. New Jersey: Lawrence Erlbaum Associates.Schetky, D.H., & Benedek, E.P. (2002). Principles and practice of child and adolescent forensic psychiatry. London: American Psychiatric Publishing.Sex, (2013) Online edition of the Oxford English Dictionary (http://www.oxforddictionaries.com/definition/english/sex).Gwartney, D. (2013). Default effects of testosterone and estradiol. Herramientas, 13, 00.BBC. (2010). Dr. Money and the Guy Without a Penis [video file]. Retrieved from http://www.youtube.com/watch?v=MUTcwqR4Q4Y&list=PL4XMCGEuCKGULWW_LekD2OU3TnLP3Loe1