My work has been a counterpoint to the view that the role division between men and women is largely predetermined by human evolutionary history. My approach to understanding gender often challenges established norms. For example, I assert that human sexual development is not always dichotomous and that gender differences fall on a continuum, not into two separate buckets.

One way to understand this is through the eyes of human beings born with anatomical characteristics of both sexes. Another is to understand how scientific understanding of the biology of sex and gender has itself been shaped by the culture which produced it. I detail both these claims in my book, Sexing the Body.


Gender and Early Childhood Development

Girls are verbal, while boys are physical— or so the traditional thinking goes. Between ages 3 and 5, girls and boys consolidate the concepts that they are of a certain sex, that their sexes are not changeable and that some behaviors are associated with particular sexes.These are the “facts of the matter”; but how do they relate to one another? How do inter-linked systems that include everything from individual physiology to media representations of sex roles and behavior produce the emergence of sexually differentiated behavior?In developing a systems theoretical framework for studying gender differentiation, one goal of my work is to break away from the centuries old nature/nurture debate in order to offer a more productive approach to understanding human development.

One interesting illustration of gender and early childhood development can be found at The Pink and Blue Project by JeongMee Yoon ( I refer to these photographs in my presentations as a vivid illustration of the integration of nature and nurture in developing gender differentiation.


Social Construct

I believe that both sex and gender are in part social constructs. But they take place in the body, and so are simultaneously biological. Dynamic systems theories link the social—which impinges on the developing body—to the body itself. Cultural experience has physiological effects.



There is a continuity between masculinity and femininity. In 1993 I published an article titled The Five Sexes that unleashed a firestorm of debate about sex and gender, with a particular focus on the intersex experience. I asserted that “the two-sex system embedded in our society is not adequate to encompass the full spectrum of human sexuality.” I had intended to be provocative, but nevertheless was surprised by the magnitude of the controversy unleashed. At the time I suggested, tongue in cheek, a five-sex system, which I later amended in The Five Sexes Revisited. Rather than identify a specific number of sexes, in the second paper I wrote “sex and gender are best conceptualized as points in a multidimensional space.”

Based on an assessment I conducted with Brown University undergraduates I also estimated intersexual birthrates to be about 1.7%, and have since been called on widely by journalists and other experts to examine these issues.


Sexual Orientation

“I am deeply committed to the ideas of the modern movements of gay and women’s liberation, which argue that the way we traditionally conceptualize gender and sexual identity narrows life’s possibilities while perpetuating gender inequality. In order to shift the politics of the body, one must change the politics of science itself.”


Sex hormones

I prefer to call estrogen and testosterone “growth hormones” instead of “sex hormones”. “The molecules we call sex hormones affect our liver, our muscles, our bones, virtually every tissue in the body. In addition to their roles in our reproductive system, they affect growth and development throughout life. So to think of them as growth hormones, which they are, is to stop worrying that men have a lot of testosterone and women, estrogen.”


I receive many requests to explain the biological nature of human sexuality. The questions usually address homosexuality, intersexuality, or transgender feelings.

In my work, I argue that the two-sex system embedded in our society is not adequate to encompass the full spectrum of human sexuality. Discrete buckets – like “nature” or “nurture”, “boy” or “girl” – are too simplistic for the inherent messiness found in nature. As I have argued in The Five Sexes and The Five Sexes Revisited, the boundaries separating masculine and feminine seem harder than ever to define. Some find the changes under way deeply disturbing. Others find them liberating. While the legal system may have an interest in maintaining only two sexes, our collective biologies do not.

My three short articles on the topic listed below are a good place to start, but I provide a list of books for further reading as well.


Animated Video on Gender Identity Development 




(Articles by Anne Fausto-Sterling are available on Research Gate)

  • Dreger, Alice D. (2002) “Intersex”, July 23.
  • Migeon, Claude (2002) “46,XY Intersex Individuals: Phenotypic and Etiologic Classification, Knowledge of Condition, and Satisfaction with Knowledge in Adulthood“. Pediatrics 110 (3): e32.
  • Williams, Nina (2002) “The Imposition of Gender: Psychoanalytic Encounters with Genital Atypicality“. Psychoanalytic Psychology 19 (3):455-74.
  • Fausto-Sterling, Anne (2000) & M. Blackless, A. Charuvastra, A. Derryck, K. Lauzanne, E. Lee, “How Sexually Dimorphic Are We? Review and Synthesis” American Journal of Human Biology 12: 151-166.
  • Fausto-Sterling, Anne (2000) “The Five Sexes, Revisited” The Sciences (July/August) pp. 18-23.
  • Fausto-Sterling, Anne (1993) “The Five Sexes”. The Sciences (March/April) pp. 20-25.



  • Richardson, Sarah (2013) Sex Itself: The Search for Male and Female in the Human Genome. University of Chicago Press
  • Drescher, Jack and William Byne eds. (2012) Treating Transgender children and Adolesceincts: An Interdisciplinary Discussion. Routledge
  • Jordan-Young, R. M. (2010). Brainstorm: The Flaws in the Science of Sex Differences. Cambridge, MA., Harvard University Press.
  • Fine, C. (2010). Delusions of Gender. New York, W.W. Norton and Company.
  • Reis, Elizabeth (2009) Bodies in Doubt: An American History of Intersex. Johns Hopkins University Press
  • Karkazis, Katrina (2008) Fixing Sex: Intersex, Medical Authority, and Lived Experience. Duke University Press
  • Valentine, David (2007) Imagining Transgender: an ethnography of a category. Duke University Press
  • Stryker, S. and S. Whittle, Eds. (2006). The Transgender Studies Reader. New York, Routledge.
  • Sytsma, Sharon, ed. (2006) Ethics and Intersex. Springer.
  • Goodman, A.; Heath, D.; Lindee, M.S. eds. (2003) Genetic Nature/Culture: Anthropology and Science beyond the Two-Culture Divide. University of California Press.
  • Preves, Sharon (2003) Intersex and Identity: The Contested Self, Rutgers University Press.
  • Williams, S.; L. Birke, G. Bendelow, eds. (2003) Debating Biology, Routledge.
  • Bloom, A. (2002) Normal, Random House.
    Byne, William Scientific American: The Biological Evidence Challenged, eBook.
  • Chase, C. (2002) Affronting Reason. GenderQueer: Voices From Beyond the Sexual Binary. J. Nestle, C. Howell and R. Wilchins. Los Angeles, Alyson Books.
  • Meyerotwitz, Joanne. (2002) How sex changed: a history of transsexuality in the United States. Harvard University Press
  • Fausto-Sterling, Anne (2000) Sexing the Body: Gender Politics and the Construction of Sexuality. Basic Books.
  • Oosterhuis, Harry (2000) Stepchildren of Nature: Krafft-Ebing, Psychiatry and the Making of Sexual Identity. University of Chicago Press
  • Dreger, Alice, ed. (1999) Intersex in the Age of Ethics. University Publishing Group.
  • Stein, Edward (1999) The mismeasure of desire: the science, theory and ethics of sexual orientation. Oxford University Press.
  • Dreger, Alice (1998) Hermaphrodites and the Medical Invention of Sex. Harvard University Press.
  • Feinberg, Leslie (1998) Trans liberation : beyond pink or blue. Beacon Press.
  • Kessler, Suzanne (1998) Lessons from the Intersexed, Rutgers University Press.
  • Feinberg, Leslie (1996) Transgender warriors: making history from Joan of Arc to RuPaul. Beacon Press.
  • Herdt, Gilbert ed. (1994) Third Sex, Third Gender. Zone Books.
  • Laumann, Edward O. et al (1994) The Social Organization of Sexuality: Sexual Practices in the United States. University of Chicago Press.