Homosexuality has been documented throughout history and is found in almost all human cultures. Twin studies suggest that homosexuality is to some extent heritable. However, from an evolutionary perspective, this poses a problem: Male homosexuals tend to have on average five times fewer children than heterosexual males, so how can a phenomenon associated with low reproductive success be maintained at relatively stable frequencies? Recent findings of increased maternal fecundity of male homosexuals suggest that the genes responsible for homosexuality in males increase fecundity in the females who carry them. Can an increase in maternal fecundity compensate for the fecundity reduction in homosexual men and produce a stable polymorphism? In the current study, this problem was addressed with an individual-based modeling (IBM) approach. IBM suggests that male homosexuality can be maintained in a population at low and stable frequencies if roughly more than half of the females and half of the males are carriers of genes that predispose the male to homosexuality.
This is a preview of subscription content, access via your institution.
Buy single article
Instant access to the full article PDF.
Price excludes VAT (USA)
Tax calculation will be finalised during checkout.
PHP script and MYSQL table instructions are available upon request by email.
Bailey, J. M., Dunne, M. P., & Martin, N. G. (2000). Genetic and environmental influences on sexual orientation and its correlates in an Australian twin sample. Journal of Personality and Social Psychology, 78, 524–536.
Bailey, J. M., & Pillard, R. C. (1991). A genetic study of male sexual orientation. Archives of General Psychiatry, 48, 1089–1096.
Borrill, P. L., & Tesfatsion, L. (2011). Agent-based modeling: The right mathematics for the social sciences? In J. B. Davis & D. W. Hands (Eds.), Elgar companion to recent economic methodology (pp. 228–259). Cheltenham, UK: Edward Elgar Publishing.
Ciani, A. C., Cermelli, P., & Zanzotto, G. (2008). Sexually antagonistic selection in human male homosexuality. PLoS One, 3(6), e2282. doi:10.1371/journal.pone.0002282.
Ciani, A. C., Corna, F., & Capiluppi, C. (2004). Evidence for maternally inherited factors favouring male homosexuality and promoting female fecundity. Proceedings of the Royal Society of London B: Biological Sciences, 271, 2217–2221.
Ciani, A. C., & Pellizzari, E. (2012). Fecundity of paternal and maternal non-parental female relatives of homosexual and heterosexual men. PLoS One, 7(12), e51088. doi:10.1371/journal.pone.0051088.
Diamond, M. (1993). Homosexuality and bisexuality in different populations. Archives of Sexual Behavior, 22, 291–310.
Eckert, E. D., Bouchard, T. J., Bohlen, J., & Heston, L. L. (1986). Homosexuality in monozygotic twins reared apart. British Journal of Psychiatry, 148, 421–425.
Ellis, L., Robb, B., & Burke, D. (2005). Sexual orientation in United States and Canadian college students. Archives of Sexual Behavior, 34, 569–581.
Evans, D. M., & Martin, N. G. (2000). The validity of twin studies. GeneScreen, 1(2), 77–79.
Gates, G. (2011). How many people are lesbian, gay, bisexual and transgender? Los Angeles: The Williams Institute of the University of California.
Gavrilets, S., & Rice, W. R. (2006). Genetic models of homosexuality: Generating testable predictions. Proceedings of the Royal Society of London B: Biological Sciences, 273, 3031–3038.
Getz, W. M. (1993). Invasion and maintenance of alleles that influence mating and parental success. Journal of Theoretical Biology, 162, 515–537.
Grimm, V., & Railsback, S. F. (2013). Individual-based modeling and ecology. Princeton, NJ: Princeton University Press.
Grulich, A. E., Visser, R. O., Smith, A., Rissel, C. E., & Richters, J. (2003). Sex in Australia: Homosexual experience and recent homosexual encounters. Australian and New Zealand Journal of Public Health, 27, 155–163.
Haldane, J. B. S., & Jayakar, S. D. (1964). Equilibria under natural selection at a sex-linked locus. Journal of Genetics, 59, 29–36.
Hamer, D. H., Hu, S., Magnuson, V. L., Hu, N., & Pattatucci, A. M. (1993). A linkage between DNA markers on the X chromosome and male sexual orientation. Science, 261, 321–327.
Heston, L. L., & Shields, J. (1968). Homosexuality in twins: A family study and a registry study. Archives of General Psychiatry, 18, 149–160.
Hutchinson, G. E. (1959). A speculative consideration of certain possible forms of sexual selection in man. American Naturalist, 93, 81–91.
Iemmola, F., & Ciani, A. C. (2009). New evidence of genetic factors influencing sexual orientation in men: Female fecundity increase in the maternal line. Archives of Sexual Behavior, 38, 393–399.
Joseph, J. (2000). Not in their genes: A critical view of the genetics of attention-deficit hyperactivity disorder. Developmental Review, 20, 539–567.
Kallmann, F. J. (1952). Comparative twin study on the genetic aspects of male homosexuality. Journal of Nervous and Mental Disease, 115, 283–298.
Kendler, K. S., Thornton, L. M., Gilman, S. E., & Kessler, R. C. (2000). Sexual orientation in a US national sample of twin and nontwin sibling pairs. American Journal of Psychiatry, 157, 1843–1846.
Kimura, M. (1962). On the probability of fixation of mutant genes in a population. Genetics, 47, 713.
King, M., Green, J., Osborn, D. P., Arkell, J., Hetherton, J., & Pereira, E. (2005). Family size in White gay and heterosexual men. Archives of Sexual Behavior, 34, 117–122.
Kirk, K. M., Bailey, J. M., Dunne, M. P., & Martin, N. G. (2000). Measurement models for sexual orientation in a community twin sample. Behavior Genetics, 30, 345–356.
Kirkpatrick, R. C. (2000). The evolution of human homosexual behavior. Current Anthropology, 41, 385–413.
Långström, N., Rahman, Q., Carlström, E., & Lichtenstein, P. (2010). Genetic and environmental effects on same-sex sexual behavior: A population study of twins in Sweden. Archives of Sexual Behavior, 39, 75–80.
MacIntyre, F., & Estep, K. W. (1993). Sperm competition and the persistence of genes for male homosexuality. Biosystems, 31, 223–233.
Maynard-Smith, J. M., & Slatkin, M. (1973). The stability of predator-prey systems. Ecology, 54, 384–391.
Mustanski, B. S., DuPree, M. G., Nievergelt, C. M., Bocklandt, S., Schork, N. J., & Hamer, D. H. (2005). A genomewide scan of male sexual orientation. Human Genetics, 116, 272–278.
Nash, G. (2001). The subversive male: Homosexual and bestial images on European mesolithic rock art. In L. Bevan (Ed.), Indecent exposure: Sexuality, society and the archaeological record (pp. 43–55). Glasgow, UK: Cruithne Press.
Rice, G., Anderson, C., Risch, N., & Ebers, G. (1999). Male homosexuality: Absence of linkage to microsatellite markers at Xq28. Science, 284, 665–667.
Richardson, K., & Norgate, S. (2005). The equal environments assumption of classical twin studies may not hold. British Journal of Educational Psychology, 75, 339–350.
Rieger, G., Blanchard, R., Schwartz, G., Bailey, J. M., & Sanders, A. R. (2012). Further data concerning Blanchard’s (2011) “Fertility in the mothers of firstborn homosexual and heterosexual men” [Letter to the Editor]. Archives of Sexual Behavior, 41, 529–531.
Roughgarden, J. (2012). Individual based models in ecology: An evaluation, or how not to ruin a good thing. Paper presented at the Philosophy of Science Association Biennial Meeting, San Diego, CA. Retrieved from http://philsci-archive.pitt.edu/9434/1/RoughgardenPSA2012IBMLecture.pdf.
Sanders, A. R., Martin, E. R., Beecham, G. W., Guo, S., Dawood, K., Rieger, G., … Bailey, J. M. (2014). Genome-wide scan demonstrates significant linkage for male sexual orientation. Psychological Medicine, 45, 1379–1388.
Seligman, M. E. (2009). What you can change and what you can’t: The complete guide to successful self-improvement. New York: Vintage.
Sell, R. L., Wells, J. A., & Wypij, D. (1995). The prevalence of homosexual behavior and attraction in the United States, the United Kingdom and France: Results of national population-based samples. Archives of Sexual Behavior, 24, 235–248.
Taylor, J. E., & Jaenike, J. (2002). Sperm competition and the dynamics of X chromosome drive: Stability and extinction. Genetics, 160, 1721–1731.
Taylor, J. E., & Jaenike, J. (2003). Sperm competition and the dynamics of X chromosome drive in finite and structured populations. Annales Zoologici Fennici, 40, 195–206.
Van de Ven, P., Rodden, P., Crawford, J., & Kippax, S. (1997). A comparative demographic and sexual profile of older homosexually active men. Journal of Sex Research, 34, 349–360.
Vasey, P. L., & VanderLaan, D. P. (2007). Birth order and male androphilia in Samoan fa’afafine. Proceedings of the Royal Society of London B: Biological Sciences, 274, 1437–1442.
Vrangalova, Z., & Savin-Williams, R. C. (2010). Correlates of same-sex sexuality in heterosexually identified young adults. Journal of Sex Research, 47, 92–102.
Whitam, F. L., Diamond, M., & Martin, J. (1993). Homosexual orientation in twins: A report on 61 pairs and three triplet sets. Archives of Sexual Behavior, 22, 187–206.
Wilson, E. O. (1975). Sociobiology: The new synthesis. Cambridge, MA: Harvard University Press.
Zietsch, B. P., Morley, K. I., Shekar, S. N., Verweij, K. J., Keller, M. C., Macgregor, S., … Martin, N. G. (2008). Genetic factors predisposing to homosexuality may increase mating success in heterosexuals. Evolution and Human Behavior, 29, 424–433.
I thank Lexo Gavashelishvili and David Tarkhnishvili for providing valuable suggestions on manuscript. I express my gratitude to Ryan Erickson and Cort Anderson for improving the use of English in the article. I also thank three anonymous reviewers and the Editor for their helpful comments.
About this article
Cite this article
Chaladze, G. Heterosexual Male Carriers Could Explain Persistence of Homosexuality in Men: Individual-Based Simulations of an X-Linked Inheritance Model. Arch Sex Behav 45, 1705–1711 (2016). https://doi.org/10.1007/s10508-016-0742-2