Origin of Sexual Orientation By rmarsh2 Jan 1, 1864 The first theory on the origin of sexual orientation was created 1864 Jan 1, 1905 The first official theory that was against the idea of Sexual identity being predetermined at birth 1905 Jan 1, 1934 The first not clear theory about the origin of sexual orientation was created 1934 Period: Jan 1, 1964 to Jan 7, 2017 Origin of Sexual Orientation Timespan Jan 6, 2013 U.S. vs. Windsor US denied same sex marriage rights to a man who sexually identified as a woman. 2013 Jan 6, 2016 Transgender Bathroom Controversy 2016 Jan 6, 2017 Most recent official theory is produced 2012