Lamanna, Mary Ann; Riedmann, Agnes; Stewart, Susan D (2014). Marriages, Families, and Relationships: Making Choices in a Diverse Society. en:Cengage Learning. p. 82. ISBN978-1-305-17689-8. https://books.google.com/books?id=fofaAgAAQBAJ&pg=PA82February 11, 2016閲覧. "The reason some individuals develop a gay sexual identity has not been definitively established – nor do we yet understand the development of heterosexuality. The American Psychological Association (APA) takes the position that a variety of factors impact a person's sexuality. The most recent literature from the APA says that sexual orientation is not a choice that can be changed at will, and that sexual orientation is most likely the result of a complex interaction of environmental, cognitive and biological factors...is shaped at an early age...[and evidence suggests] biological, including genetic or inborn hormonal factors, play a significant role in a person's sexuality (American Psychological Association 2010)."
Lamanna, Mary Ann; Riedmann, Agnes; Stewart, Susan D (2014). Marriages, Families, and Relationships: Making Choices in a Diverse Society. en:Cengage Learning. p. 82. ISBN978-1-305-17689-8. https://books.google.com/books?id=fofaAgAAQBAJ&pg=PA82February 11, 2016閲覧. "The reason some individuals develop a gay sexual identity has not been definitively established – nor do we yet understand the development of heterosexuality. The American Psychological Association (APA) takes the position that a variety of factors impact a person's sexuality. The most recent literature from the APA says that sexual orientation is not a choice that can be changed at will, and that sexual orientation is most likely the result of a complex interaction of environmental, cognitive and biological factors...is shaped at an early age...[and evidence suggests] biological, including genetic or inborn hormonal factors, play a significant role in a person's sexuality (American Psychological Association 2010)."
