Sexual orientation refers to the direction of an individual's sexuality, usually conceived of as classifiable according to the sex or gender of the persons whom the individual finds sexually attractive.
Kinsey Reports American Psychological Association Magnus Hirschfeld Affectional orientation Simon LeVay Twin study Transgender Homosexuality American Academy of Pediatrics Kinsey scale Alfred Kinsey J. Michael Bailey Intersexuality Asexuality Sigmund Freud Bisexuality Heterosexuality Ascribed characteristics Vaginal photoplethysmograph Xq28 Fruitless (gene) Paul Gebhard Evelyn Hooker Innate bisexuality Penile plethysmograph Wilhelm Fliess Dean Hamer Gender variance Journal of Homosexuality Kinsey Institute for Research in Sex, Gender and Reproduction Kinsey David Satcher Fritz Klein Richard von Krafft-Ebing Sexual norm Karl Heinrich Ulrichs Centre for Addiction and Mental Health Terminology of homosexuality Cisgender Gynephilia and androphilia
