The culturally prevailing (or “authorized”) biography, entrenched as it is in stereotypes, is, according to the authors, “about libido, aggression, focus [and] facility with science and math. It’s gendered, channelling myriad elements of masculinity.” The dominant narrative has indeed cemented T as the male sex hormone, with oestrogen its female counterpart. Thus, T and oestrogen are seen as being locked in a heteronormative, mutually exclusive binary. This framing, as the authors make clear from the outset, is already limiting insofar as, for example, women also produce T and require it for healthy functioning, and T is required for a range of functions, not just limited to reproductive structures and physiology (and therefore sex and sex differences). Limiting testosterone in this way, the authors argue, has consequences — not least of which are the structural inequalities that arise when T comes to be associated with particular characteristics, such as a predilection for technology or engineering. Or it operates as a scapegoat for bad behavior, such as the 2008 stock market crash. The problem, as the authors succinctly put it, is that this approach “frames social issues as a matter of the chemicals functioning inside individual bodies, leaving scant room to consider power asymmetries, structural arrangements, or histories and their current material consequences.”
In their chapter on “Violence,” the authors seem eager to rebut the correlation between testosterone and human aggression. As they argue, rather than closing the door on this link once and for all, given the largely negative evidence available, researchers instead have seen “an intriguing doorway to new knowledge rather than indication of a dead-end street.” The authors’ urge to conclusively close this door seems somewhat premature, however, since recent studies have found that testosterone and aggression are not entirely unrelated, although the link may not be explicitly direct.  Nonetheless, the authors do make a fair point that testosterone should not be used, on its own, as a scapegoat for aggressive behavior or as a way to malign and stigmatize certain groups, such as working-class people, people of color, or males generally.
One of the most thought-provoking moments in the book occurs in the chapter on “Athleticism,” when the authors discuss the medicalization and pathologization of those whose atypical sex traits seem to set them outside the standard gender binary, specifically women with very high T levels. As the authors show, the regulations governing women’s sports — in particular, those set out by the International Association of Athletics Federation and the International Olympic Committee — target women whose bodies do not conform to normative gender binaries. These rules position such women “outside the group of women athletes who deserve fairness, and amplify widespread prejudices about difference rather than addressing any demonstrated problem in women’s sports.” Without a doubt, women who happen to naturally produce more testosterone than other women are no less women if they identify as such, and it is unfortunate that sports regulations treat them as if they are not. And, of course, one should also take into account the divergent evidence of T’s effects on athletic performance, which the authors clearly present.
One criticism of the book is that trans men are insufficiently considered. In the rare instances where they are mentioned, the authors either seem dismissive of their experiences or impose a somewhat patronizing narrative of how they should supposedly feel. As they argue, “[s]ome evidence suggests that trans men experience an increase in sexual function after transition, but this is unsurprising: trans people are forced to narrate sexual dissatisfaction in order to meet clinical criteria for medical interventions.” The authors even argue that an increase in sex drive may also be the result of a placebo effect. That may or may not be the case, but why should the authors assume this, and why is the evidence to substantiate such a view not provided? In short, the authors simply erase the complex record of trans experience, presumably so that it does not contradict their claims about the effects of testosterone more generally.
The dearth of exploration of trans men’s experiences on testosterone is a shame. Granted, the authors are largely exploring endogenous T, which is naturally produced within the body, rather than exogenous T, which is (generally) medically prescribed, and perhaps this may be considered a justification for the exclusion of a discussion of trans men. Yet their discussion of exogenous T as a pharmaceutical precision technology, and the manner in which endogenous T is meant to inform the effects of exogenous T, for example, implies that the authors do not see a distinction between the two. In any case, there is ample scholarly and anecdotal evidence that trans men on testosterone experience an increase in sex drive, among other things.  There is no reason to assume these testimonies are untruthful or that these men are not fully aware of the complexities of the effects of testosterone. Of course, this is not to argue that all trans men will experience an increase in sex drive on testosterone, but neither is it to argue that testosterone will absolutely not play a role in some trans men. As a number of firsthand accounts demonstrate, it possibly does. This inattention is all the more surprising given that the authors admit as much in a different context: as they argue, “It’s not to say that T is completely unrelated to sexual function, including libido, but to note that the relationships are complicated and limited.”
Despite this failing, Testosterone: An Unauthorized Biography is a beautifully written and important book. The authors present strong and persuasive arguments that demythologize and defetishize T as a molecule containing quasi-magical properties, or as exclusively related to masculinity and males. As they persuasively argue:
T is often a mechanism for individualizing the social, most often with gender. Too often, T is invoked as an apologia for status quo sexism in which sexual violence, higher male salaries, men’s overrepresentation in prestigious occupations, and the tasking of women with domestic drudgery must all be accepted as natural and inevitable.
These essentialist claims function to marginalize, elide, or exclude other factors that are just as crucial, such as socialization, institutional structures, and power dynamics that replicate and perpetuate the status quo via entrenched, heteronormative gender binaries.
Linda Roland Danil holds a PhD from the School of Sociology and Social Policy at the University of Leeds.
 See, for example, J. M. Carré et al., “Testosterone Modulates Aggression in Dominant and Impulsive Men,” Biological Psychiatry 82.4 (2017): 249–256. In this study, exogenous T on its own did not modulate aggressive behavior; however, T’s effects on aggression were strongly influenced by variation in trait dominance and trait self-control. T therefore did cause an increase in aggressive behavior, but only among men who scored relatively high in trait dominance or low in trait self-control.
 For academic research, see, for example, R. Dadasovich et al., “Testosterone and Sexual Risk Among Transmen: A Mixed Methods Exploratory Study,” Culture, Health and Sexuality 19.2 (2017): 256–266. Popular journalistic accounts include L. Moore, “What It’s Really Like to Transition From Female to Male,” Cosmopolitan (January 15, 2016); and S. Karlan, “Here’s What Trans Men Wish They’d Known Before Starting Hormone Therapy,” BuzzFeed (September 8, 2016).