A Situational Definition of Sex

By Vadim Shteyler

In a previous blog post, I introduced Dutee Chand, a world-class sprinter suspended from national and international competitions by the International Olympic Committee (IOC) and the International Association of Athletics Federations (IAAF). According to the policies of these organizations, an athlete with testosterone levels in the male range cannot compete in the female category. As I discuss in my previous post, by creating a definition of sex that is meant to only be applicable in sports, the IOC and IAAF effectively created a situational definition of sex.

Sex is poorly defined.

From the debate that arose after Dutee Chand’s suspension—as well as from other recent controversies surrounding sex-segregation in bathrooms, prisons, the military, and many other settings—it is evident that people cannot agree on a definition of sex. In the United States, sex is defined differently in different contexts. At birth, it is defined by external genitalia. In genetic testing, it is defined by chromosomal makeup. In everyday life situations, it is defined by clothes, hair, and other select physical features. 

Some may argue that these are all examples of the different ways that sex is perceived, not defined, and that these are just examples of how we use heuristics to distinguish between the sexes. In an attempt to maintain a universal definition of sex, they may argue that sex is truly defined by a common underlying biological process. However, this post will focus only on the practical aspects of sex-segregation, as used in law and policy, and not on sex as an abstraction. Since the overwhelming majority have not had their genomes and hormone profiles examined, the way sex has been distinguished has been, in most life situations, the way it has been defined. Moreover, the most reductionist definitions of sex are not practical because they are not comprehensive (as many of the biological processes that influence sex development remain unknown). They are untestable (as assays for the majority of these processes are not available). And they remain controversial (as demonstrated by lessons from people with certain Disorders of Sexual Development—read more about Androgen insensitivity Syndrome for one example).

Sex should not be universally defined.

As Talia Bettcher describes in an article published in Signs, many trans subcultures have their own definitions of sex. Among the different trans subcultures, some see themselves as transcending sex, some define themselves as trans men or trans women, while others define themselves as unequivocally male or female. Even among the latter group, some undergo surgeries, some take hormones, some get silicone injections but many do not. A trans woman can define herself as a true female without any desire for genital reconstruction surgery. She might live as a female among all of her friends and loved ones while being seen as a male whenever she uses a public restroom, or forced to live as a male if she were to be incarcerated.

As the lives of many trans people illustrate, it is often most ethical to use a person’s own identity as the definition of their sex. In recognition of this, California is allowing death certificates of trans people to document the sex they lived as, as opposed to recording the one they were born in (read more about the Respect After Death Act). Simultaneously, however, defining sex differently, depending on the situation, sometimes makes most sense.

Sex can be defined situationally.

In sports, if people would agree that the sex performance gap should be controlled with separate male and female categories, and if there were one measurable factor that accounted for this performance gap, it would be reasonable and ethical to define sex by the measure of that factor (Note: for this discussion, I will accept the first two premises as true, though they are ethically controversial). It just so happens that endogenous testosterone does not correlate well with improved athletic performance. If a factor accounting for sex differences in sports were to exist, accepting that this way of categorizing sex is situational would place sex categories as morally equivalent to weight categories in boxing.

Many countries, including Japan, Egypt, India, Brazil, and Taiwan, introduced female-only train cars as a short-term solution for the rising incidence of sexual offenses in public transportation. Again, this discussion will not focus on the ethics of sex-segregating train cars but rather on the way sex is defined in the policies. Several days ago, United Kingdom Transport Minister Claire Perry announced considering a similar policy (see news coverage here). Though the train cars are for females only, it makes sense that Japan allows young boys and persons with disabilities and their assistants to board these cars. It also makes sense that SheTaxi, a female-only taxi service introduced in New York City this month, allows males to ride if they are with the female who hailed the cab. In these cases, female is defined as any person who is both unlikely to commit a sexual offense against a female and is perceived to be unlikely to commit a sexual offense against a female.


I separate two reasonable ways of conceptualizing sex in law and policy. The first distinguishes the sexes as a demographic (e.g., birth certificates, legal documents, etc.) and is often seen as a reflection of a person’s identity. The second, situationalist conceptualization, is meant to differentiate qualities that often correlate with sex but are not meant to reflect on a person’s identity. Like with any policy, the way situationalist definitions are enforced must align with the qualities they aim to differentiate in order to avoid being discriminatory.

Regrettably, as of the date of this post, Dutee Chand has still not been permitted to compete.