Sexual orientation is defined as an often enduring pattern of emotional, romantic and/or sexual attractions of men to women or women to men (heterosexual), of women to women or men to men (homosexual), or by men or women to both sexes (bisexual).
(American Psychological Association. (2008). Answers to your questions: For a better understanding of sexual orientation and homosexuality. Washington, DC: Author. [Retrieved from www.apa.org/topics/lgbt/orientation.pdf.])