Book Reviews

Sarah S. Richardson, Sex Itself: The Search for Male and Female in the Human Genome, University of Chicago Press, 2013

Following the glorious tradition of feminist philosophers and scholars of science from the 1980s onward such as Evelyn Fox-Keller, Helen Longino, Anne Fausto-Sterling, and others who revealed how popular notions of masculinity and femininity infiltrated and shaped the content of scientific knowledge, Sarah S. Richardson’s book Sex Itself: The Search for Male and Female in the Human Genome (2013) deserves a place on the shelf with this canonical literature. It addresses one of the most celebrated symbols of biological sex binary: the X and Y chromosomes. The X and Y chromosomes, we learn, were not given the role of “sex chromosomes” upon their discovery in 1890 and 1905, respectively. Their transformation into the ultimate biological signifiers of male and female during the next five decades was neither inevitable nor free from significant theoretical and empirical challenges. Rather, the X and Y chromosomes, objects of scientific study, were gendered via the various stages of scientific inquiry and methodology. The implicit promise embedded in the human genome project to decode human differences and identify the genetic elements of maleness and femaleness make Richardson’s book a crucial contribution that outlines a much-welcomed reflection of this scientific endeavor.

Whereas during the late 19th century biologists understood “sex” as a “complicated, spectrum-like, and highly variable phenomenon” (24), the beginning of the 20th century saw biologists expressing a dimorphic vision of sex differences, with models that attempted to identify clear and distinguishing elements between males and females. The discovery and study of the X and Y chromosomes fit well within the emerging dimorphic vision of sex overall. Moreover, it led to the gradual replacement of metabolic and hormonal models of sex differences by a genetic model of sex, casting the X and Y chromosomes as the new symbols of biological dimorphic sex.

Richardson’s book addresses an issue that has become important to ethicists, jurists, and scientists in recent years: how to account for biological differences between humans in an ethical, productive manner. With respect to genetic differences between males and females, the book takes up the incredibly daunting challenge of how to conduct genetic research on sex differences that yields beneficial results but that also avoids the pitfalls of biological determinism that feed sexist agendas. Through the book’s historic narrative and analysis of the future trajectory of genetic research, Richardson argues that although gender conceptions have a history of distorting scientific research, they could potentially be used constructively. Beliefs about gender are part of the social backdrop in which scientific research operates and therefore cannot simply be identified and surgically removed. Instead, Richardson offers a theoretical approach she calls “gender modeling,” which aspires to understand, on a descriptive level, “what work does gender do in this case?” rather than focus on the possible prejudice that led to gender conceptions in (16). After reviewing the different chapters of the book, I will advance the speculation that the paradigm of “sex itself, the idea that scientific inquiry into the deep biological layers of the body could reveal the essence of sex, might be fading away.

Sex Itself proceeds in ten chapters. Chapter 1 introduces the bio-cultural concept of “sex itself” within the context of genetic research and feminist analysis of science, and the overall argument of the book. Chapters 2 through 4 provide a historical chronology of scientific research leading to the theory that the X and Y chromosomes are the biological markers of sex and gender: maleness and femaleness. When the X and Y were discovered, they were first called the “odd chromosomes.” The growing interest in fertilization and biological sexual dimorphism in early 20th century drove scientists to try to link the function of the odd chromosomes to existing theories about sex differentiation. Nettie Stevens and Edmund Wilson created a fundamental theory of the odd chromosomes as the biological element that determines sex, transforming them from “odd” into “sex” chromosomes (34). The theory of X and Y as sex chromosomes implied that femaleness and maleness are separate, distinct routes of development. Many decades of research using this framework did not produce any workable theory of genetic sex differences; nevertheless, the emerging molecular science of sex of the time gendered the X and Y chromosomes in effect by focusing on their empirically nonproven relationships to maleness and femaleness.

In 1959, it was discovered that the existence of a Y chromosome is critical for the development of testes (77). This discovery bolstered the notion that the Y chromosome is the biological “seat of maleness.” Chapters 5 and 6 provide two exemplary case studies on how gender conceptions attached to the X and Y chromosomes produced empirically invalid and methodologically shaky theories regarding their operation. One such hypothesis was the “XYY super-male” theory. After blood samples collected in a high-security psychiatric hospital indicated a high rate of males with extra Y chromosomes, it was theorized that an extra Y might be a cause for propensity to aggression. This theory provided an easy causal chain from chromosome (Y) to gonads (testes) to gender (maleness). Despite later studies demonstrating that XYY males had no greater propensity for aggression and that their offences were actually less aggressive and violent than those of XY males, the theory persisted for another decade and a half. After Chapter 6, which discusses a parallel process associating the X chromosome with femaleness, partly through theories that focused on the connection between the X chromosome to female autoimmunity, Chapters 7 and 8 take us to a new period in genetic research in which feminist criticism of science has taken root and began exposing gender biases in biological and medical research.

When the SRY gene was discovered on the Y chromosome in 1990, it was given the role of the “master gene,” which allegedly switched on and off masculine sex development. This theory did not last and, today, the SRY gene is known to be one among other possible genes that direct the genetic development of testes and ovaries. This realization is, at least partly, attributed to feminist critiques of science that applied a gender-conscious perspective to the model’s assumptions and revealed theoretical and empirical failings. Biologist Jennifer Graves, a leading scientist in the field of sex chromosomes, was among the first to expose the gap between existing evidence and envisioned expectations regarding the “switch” model for the SRY gene. In a 2000 paper, she located her criticism of the “switch” model within a feminist discourse about science and argued that masculine ideas about the dominance of the Y chromosome and “macho” conceptions of the SRY gene misled researchers to ignore contradictory evidence and sustain the weak theory (137). As Richardson further demonstrates, by the time Graves identified her criticism as “feminist,” gender criticism and critical perspectives in science had become a normalized practice that contributed to a constructive thinking on how gender ideologies infiltrate and shape scientific knowledge about biological sex differences.

In Chapter 8, we learn about Graves’s later feminist criticism of a different genetic theory addressing the deterioration of the Y chromosome. The revelation that special genes located on the Y chromosome have been slowly vanishing for the last 300 million years became conceptually interlinked with social anxieties about the disappearance of maleness. Were men doomed, or would the Y chromosome’s resourcefulness save them? Two leading scientists in the field took up this controversy. Based on the rate of gene deterioration, Jennifer Graves and another scientist, Ross Aitken, predicted the Y chromosome would become extinct in approximately ten million years. David Page a medically trained geneticist, took offence at the degeneration theory and thought the Y chromosome was a victim of negative male stereotypes promoted by feminists (158). He later suggested a counter theory—that the Y chromosome would acquire male fertility genes that would overcome the projected deterioration (162). Although public judgment of their explanations for the phenomenon was asymmetrical, as Graves alone was accused of being “gender biased,” Richardson suggests that recognizing the role that gender plays in these models is a blessing. The creation of highly developed scientific models and hypotheses that are conscious to their interaction with contemporary gender politics by Page and Graves cannot be explained as mere “gender bias”, but rather should be called “gender valence.” Unlike biases that operate invisibly and unreflectively, “gender valence” brings gender to the forefront and exposes it to critical observation—to be, we hope, applied symmetrically.

The last two chapters discuss the prospects of gender/sex genetic research in the genomic and post-genomic age. In Chapter 9, Richardson examines the claim news reports had made, interpreting the work of scientists L. Carrel and H. F. Willard, whereby males and females differ genetically by 2%—greater than the difference between chimpanzees and humans, stating that females and males are “different species.” Richardson seeks to debunk each part of this claim, on both empirical and conceptual grounds and offers an alternative, more perceptive way of explaining genetic sex differences: “sex as a dynamic dyadic kind” (197). Richardson suggests that we regard this case study as an example of how a powerful new language about the genome can be used to revive old frameworks of conveying differences between groups of humans that disturbingly echo a comparison to apes.

Chapter 10, which concludes the book, uses the lessons learned from research on the X and Y chromosomes to forge concrete analytical tools that could be applied in the field of genetic research on sex-based biology and medicine, which currently enjoys enormous political and institutional support by the US women’s health movement. Within the justified efforts to advance a better understanding of women’s particular health issues and to remedy systematic failures of scientific methodology that led to historic ignorance regarding women’s disparities, Richardson reminds us that research on sex differences within the sex-based biology movement can be a double-edged sword and that we should therefore elaborate to construct a gender-critical perspective about this new, robust strand of research as it moves forward.

One of the most central concepts the book expounds on within its chapters is “sex itself,” construed by Richardson as an object of scientific quest into the body. The fascination with finding the essence of sex within the inner, unknown layers of the body in the 20th century seemed both feasible and promising at the time. Ironically, the separation between sex and gender promoted by feminist advocates further cemented the notion that a biological element tattooed on the body’s infrastructure can represent the true essence of sex. Unlike sex, gender was located in the cultural and social worlds and understood to be flexible and not necessarily dichotomous. However, biotechnological advancements transformed some biological elements such as hormones, genitals, and tissues to also become flexible and easy to alter through medication or plastic surgery. These developments placed even greater weight on the order and clarity provided by genetic sex theory, as opposed to the “soft” easy-to-change biological sex elements, that sex chromosomes served as a stable, unchangeable, and irreducible biological truth. “While hormones and culture help to shape gender, genetics alone, it is thought, can reveal, “sex itself” (9).

Richardson is correct to recognize that the search after “sex itself” is, in many ways, a search for stability in times of changing bodies and social norms. The “natural body,” often conflated with the “biological body,” is often imagined as a site of consistency and order that yields a set of normative and practical implications. As legal scholar Liz Emens demonstrates, if a subject is treated as “natural,” a set of implications is likely to apply to that subject: first, that the subject is immutable as a descriptive matter (or at least, difficult to change), and second, that the subject should not be required to change as a normative matter. As Emens shows, these assumptions have some force in different legal doctrines pertaining to discrimination and accommodation and, therefore, different identity groups, including people with disabilities, sexual and racial minorities, women or the elderly, use this set of assumptions as a matter of legal strategy. This, for example, helps explain why some groups such as sexual minorities or trans people often promote a “natural” characterization of their differences through various biomedical theories and studies. The popular logic of ‘nature’ somewhat endorsed in the law suggests that if a condition is immutable it enjoys an inherent normative value and should not be forced or expected to change. Opponents to reforms led by such groups often argue that these differences are fictional, having no bearing on the body itself, and ought to be ignored or even eliminated.

In this context, Richardson’s identification of the sex chromosomes as a crucial site in which both natural and social orders are negotiated and justified is revealing. One of the most vivid examples for this concept can be found in recent public debate about the use of bathrooms by transgender students in educational institutions. Conservative voices usually bring the X and Y chromosomes to make the point that sex is fixed and immutable: “There are only two things that make me a man, and they are my X chromosome and my Y chromosome . . . . People have the right to feel that they should not be the gender that God gave them . . . . However, the fact that some people do not live in reality or that some wish reality were not true, does not entitle them to a special bathroom in a public university.” (Gershenson) In this cultural and legal context, the sex chromosomes viewed as the locus of “sex itself” are not only biological carriers of genes and DNA but also normative carriers of social values and arrangements.

One of the most intriguing questions that arises is this: what does the future hold for the sex chromosomes in the age of gene editing? It seems that with biotechnological developments, even sex chromosomes—the hard core of “sex itself”—are becoming emendable. Studies from recent years examined the possibilities of ‘sex reversal’ on mice through modifying genes related to gonad determination. In 2009, a research group found that ablation of the FOXL2 gene in mice ovaries can reprogram their development into testosterone-producing testes (Uhlenhaut et al). A 2011 study found a parallel process in testes, which were reprogrammed to produce estrogen after the DMRT1 gene was deleted (Matson et al). Just recently, a lab succeeded at using CRISPR technology to masculinize female cattle by adding the SRY gene to their X chromosomes (Rosenblum). Not surprisingly, these developments are publicized in highly gendered “clickbait” language including: “From Minnie to Mickey (and all they did was turn off a gene),” (Connor) and “Researchers Discover Sex-Change Gene.” (Anderson-Minshall) Moreover, these articles speculate about the future implications for sex change in humans, to be used by the transgender community, or for DSD conditions (Disorders of Sex Development) (Geen).The emerging capacity to edit, change, or add genes to living mammals seems to relocate “sex chromosomes” from the hard-core to the soft-changing elements of sex. Accordingly, we can expect that future biotechnological advancements and research will continue to hollow out “sex itself” from other purportedly stable and immutable biological elements.

If so, what then is the future of “sex itself” in the age of mutability? Would the increasing malleability of bodies boost scientific motivation to search for the essence of “sex itself” in other unexplored inner locations of the body or, alternatively, if biological sex in no longer understood to be a constant and stable element, would that somehow make the sex/gender distinction useless or the normative attachments to “nature” collapse altogether? Looking ahead to the growing sex-based medicine movement, it appears that scientific research on sex differences is prospected to grow. Nevertheless, it might be that research in the context of sex-based medicine will revert to the old contingent, spectrum-like concept of sex, or alternatively progress toward a model of individual differences or to an alternative related grouping basis, like the brain mosaic approach (Joel). Possibly, this grand research project would orient its hypotheses, working models, and studies to fulfill the purpose of improving health, rather than of finding the holy grail of sex differences.

Richardson’s book is highly recommended to anyone interested in a skilled and illustrative gender analysis of a scientific field and theory. Other than its monumental contribution to classic works on the intersection of science and gender, many of the book’s qualities make it especially educational for graduate and undergraduate students. Its language is clear and guides the reader through argument’s various stages. The book does an excellent job of translating complex genetic and chromosomal theories for the nonexpert reader, without over-simplifying them, along with preserving a richness of theory, evidence, and context. The book does a great service to the field of feminist analysis of science by illustrating how sensible skepticism to empiricism from a gender-conscious point of view can generate a constructive contribution to a field of knowledge.

Maayan Sudai

Harvard Law School

Cambridge, MA, USA



Anderson-Minshall, Diane. “Researchers Discover Sex-Change Gene.” The Advocate, 21 July 2011.

Andrew Rosenblum, “Meet the Woman Using CRISPR to Breed All-Male ‘Terminator Cattle,’” MIT Technology Review,accessedApril 12, 2018,

Clinton K. Matson et al., “DMRT1 Prevents Female Reprogramming in the Postnatal Mammalian Testis,” Nature 477, no. 7363 (September 2011): 238,

Connor, Steven. “From Minnie to Mickey (and All They Did Was Turn off a Gene).” The Independent, 11 Dec. 2009.

Daphna Joel et al., “Sex beyond the Genitalia: The Human Brain Mosaic,” Proceedings of the National Academy of Sciences 112, no. 50 (December 15, 2015): 15468–73,

Geen, Jessica. “Gene Discovery Could Make Gender Reassignment Easier.” PinkNews, 11 Dec. 2009,

N. Henriette Uhlenhaut et al., “Somatic Sex Reprogramming of Adult Ovaries to Testes by FOXL2 Ablation,” Cell 139, no. 6 (December 11, 2009): 1130–42,

Olga Gershenson, The Restroom Revolution: Unisex Toilets and Campus Politics, in Toilet: Public Restrooms and the Politics of Sharing 200 (Harvey, Molotch, Laura & Noren eds., 2010).

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