/22/ Untuk makalah ilmiah penemuan ini, lihat M. Azim Surani, Naoko Irie, Leehee Weinberger, et al., “SOX17 Is a Critical Specifier of Human Primordial Germ Cell Fate, Cell, Vol. 160, Issues 1-2, 15 January 2015, hlm. 253-268, pada http://www.cell.com/cell/abstract/S0092-8674%2814%2901583-9; lihat reportase populer BBC Crew, “Two-dad babies could soon be a reality: Scientists have made human egg and sperm cells using skin from adults of the same sex”, Science Alert, 25 February 2015, pada http://www.sciencealert.com/two-dad-babies-could-soon-be-a-reality.
/23/ Simon LeVay, Gay, Straight, and the Reason Why: The Science of Sexual Orientation (New York, N.Y.: Oxford University Press, 2011), hlm. xiv-xv.
/24/ Laura S. Allen dan Roger A. Gorski, “Sexual Orientation and the Size of the Anterior Commissure in the Human Brain”, The Proceedings of the National Academy of Science, USA, Vol. 89, August 1992, hlm. 7199-7202, pada https://timedotcom.files.wordpress.com/2015/03/7199.full.pdf.
/25/ Lihat kolom Kelly Servick, “Study of gay brothers may confirm X chromosome link to homosexuality”, Science, 17 November 2014, pada http://news.sciencemag.org/biology/2014/11/study-gay-brothers-may-confirm-x-chromosome-link-homosexuality. Untuk makalah ilmiah kajian ini, lihat J.M. Bailey, Alan R. Sanders, E.R. Martin, et al., “Genome-Wide Scan Demonstrates Significant Linkage for Male Sexual Orientation”, Psychological Medicine, Vol. 45, Issue 07, May 2015, hlm. 1379-1388, pada http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=9625997&fileId=S0033291714002451.
/26/ Lihat bab 10 buku LeVay, Gay, Straight, and the Reason Why: The Science of Sexual Orientation (New York, N.Y.: Oxford University Press, 2011).
/27/ Lihat Lalumière ML, Blanchard R, Zucker KJ, “Sexual orientation and handedness in men and women: A meta-analysis”, NCBI. Psychological Bulletin, July 2000, No. 126 (4), hlm. 575-592, pada http://www.ncbi.nlm.nih.gov/pubmed/10900997.
/28/ Simon LeVay, The Sexual Brain, hlm. 118.
/29/ Lihat Rahman Q, Clarke K, Morera T, “Hair whorl direction and sexual orientation in human males”, NCBI. Behavioral Neuroscience, April 2009, No. 123 (2), hlm. 252-258, pada http://www.ncbi.nlm.nih.gov/pubmed/19331448.
/30/ Kelly Servick, “Study of gay brothers may confirm X chromosome link to homosexuality”, Science, 17 November 2014, pada http://news.sciencemag.org/biology/2014/11/study-gay-brothers-may-confirm-x-chromosome-link-homosexuality.
/31/ Lihat Nicolas DiDomizio, “A Surprising Number of Straight Men Are Having Sex With Other Men, Says The CDC”, Connections.Mic, 8 January 2016, pada http://mic.com/articles/132129/a-surprising-number-of-straight-men-are-having-sex-with-other-men-says-the-cdc#.iZmKZqHq8.
/32/ Lihat Sara Reardon, “Epigenetic ‘tags’ linked to homosexuality in men: Twin study reveals five DNA markers that are associated with sexual orientation”, Nature, 8 October 2015, updated 12 October 2015, pada http://www.nature.com/news/epigenetic-tags-linked-to-homosexuality-in-men-1.18530.