Definitions

ACCOMMODATION – The process of adapting or adjusting to someone or something without changing the underlying goal or design, e.g., in a workplace or educational program. In the context of sport, accommodation means adjusting an aspect of girls’/women’s event to include trans girls with male sex-linked advantages in a way that does not diminish participation and competitive opportunities for females. Examples of accommodations already in use in sport include handicapping, separate heats, separate scoring and/or separate and equal teams. This list is not exhaustive.

ANTI-DOPING – The effort against doping in sport. Doping is the use of prohibited substances and methods. Prohibited Substances Lists in the United States are maintained by the United States Anti-Doping Agency (USADA) and the National Collegiate Athletic Association (NCAA). Testosterone is a steroid on both Prohibited Substances Lists. Its exogenous use by athletes is banned. The testosterone levels of international-caliber athletes are monitored by regular urine and blood tests to ensure they do not fluctuate beyond both their own naturally-occurring levels, and the normal group ranges for their sex.

CISGENDER (CIS) – An adjective that describes a person who is neither transgender nor gender fluid. It is also used to describe a person whose gender identity is consistent with their natal sex.

CIS MALE – A person whose biological sex is male who is neither transgender nor gender fluid. 

CIS FEMALE – A person whose biological sex is female who is neither transgender nor gender fluid. 

COMPETITIVE FAIRNESS – The state of play when the rules reflect — and events are conducted — consistent with the design of the sport. For example:

  • Weight categories are considered fair when groups of comparably sized athletes are matched against one another. For example, a wrestling match is considered fair when the competitors compete in their narrowly defined weight classes and referees ensure that competitors’ actions are authorized from within a range of permissible maneuvers. 
  • Age categories are fair when they recognize and mitigate competitive differences conferred on the body due to the age of the competitor.
  • Similarly, sex segregated sport classifies athletes by their biological sex because of the significant performance gap between male athletes and female athletes, and to ensure that female athletes have the same competitive opportunities as their male counterparts. In this context, competitive fairness requires rules that safeguard the female category and the female athletes who reasonably rely on its integrity.

CONFIDENTIAL MEDICAL INFORMATION – Information, including protected health information (PHI), that is normally treated confidentially but is relevant for the determination of eligibility for sports participation and therefore shared in a limited way for this limited purpose.

FEMALE – An individual whose biological sex is female. Biological sex is sometimes referred to as natal sex. In contrast with males, females have ovaries, not testes; they make eggs, not sperm; and their endocrine system is estrogenic, not androgenic.

GENDER — Sometimes used as a synonym for sex; or to connote the complex relationship between physical sex-linked traits and one’s internal sense of self as male, female, both, or neither; or one’s sex-related expression.

GENDER AFFIRMING HORMONES – Medication taken by some trans people to counter their biological sex and affirm their gender identity. For example, trans girls/women may take estrogen to counter their male secondary sex traits and to feminize their bodies. Similarly, trans boys/men may take testosterone to counter their female secondary sex traits and to masculinize their bodies.

GENDER AFFIRMING SURGERY – Procedures undertaken by some trans people to construct or remove secondary sex traits to better reflect their gender identity, e.g., surgery to remove or construct breasts, and/or surgery to remove testes or ovaries and/or construct gender-conforming genitals.

GENDER IDENTITY – A person’s deeply held inner sense of themselves as male, female, fluid, or neither. A person’s gender identity may be different from their biological sex.

LEGACY ADVANTAGE – The permanent or long-lived physical effects of experiencing puberty in the male body. The term refers to the considerable size and strength advantages that remain even after hormone treatments or surgical procedures.

MALE – An individual whose biological sex is male. Biological sex is sometimes referred to as natal sex. In contrast with females, males have testes, not ovaries; they make sperm, not eggs; and their endocrine system is androgenic not estrogenic.

PERFORMANCE GAP – The percentage difference between male athletic performances and female athletic performances that result from biological sex-linked differences. Some individual females surpass some individual males, but depending on the sport and event, the gap between elite male performances and elite female performances overall generally ranges from 8-20%, and up to 50% in sports and events featuring explosive power. The very best elite female performances are regularly surpassed by non-elite male performances. Together with the commitment to sex equality, the substantial performance gap justifies separate sex teams and events.

PLAYING-SAFETY – The physical safety of athletes on the field of play.

PUBERTY – The period of sexual maturation and the development of fertility. Sexual maturation includes the development of secondary sex characteristics—the physical features associated with a male phenotype on the one hand, and a female phenotype on the other. In girls, the onset of puberty is generally between ages 8 and 13. In boys, it is generally between ages 9 and 14.

SEX ASSIGNED / RECORDED AT BIRTH – The designation of a newborn child’s sex on their official birth record based on inspection of their external genitalia. This designation may be incorrect in the case of an infant with a difference of sex development (DSD) that affected the development of their genitals. Sex recorded on birth certificates, passports, or drivers’ licenses may or may not reflect biological sex and should not be determinative of eligibility for competition.

SEX / BIOLOGICAL SEX – Male or female, one of two classifications by which most organisms are grouped on the basis of their reproductive organs and functions. A person’s sex also refers to the cluster of sex-linked characteristics or traits—i.e., chromosomal, gonadal, endocrinological (hormonal), and phenotypic characteristics, commonly used to distinguish males from females.

SEX-LINKED DIFFERENCES – Physical and physiological differences that are tied to being biologically male or biologically female. For purposes of sport, the main sex-linked differences are tied to the endogenous (natural) production in biological males of much higher levels of testosterone beginning from the onset of male puberty and continuously throughout the competitive athletic career.

SEX SEGREGATION – Refers to separating people by sex or by particular sex-linked traits such as testosterone. Formal sex segregation in competitive sports is constitutional because it is empowering not subordinating, and because it is the only way to ensure that females as a group have the same sports opportunities, experiences and successes as males as a group.

TESTOSTERONE / TESTOSTERONE RANGES – A hormone classified as an anabolic, androgenic steroid that builds tissue. In childhood, males and females produce about the same, small amount of testosterone. At the onset of puberty, the male testes begin to produce much more than the female ovaries. From that point forward, the normal female range[1] remains low and narrow, from 0.06 to 1.68 nmol/L, and the normal male range is relatively high and wide, from 7.7 to 29.4 nmol/L.

TRANSGENDER (TRANS) – An adjective describing a person whose gender identity is not the same as their biological sex. The person may or may not choose to transition medically through the use of gender-affirming hormones or surgery.

TRANS BOY/MAN – A person whose biological sex is female, while their gender identity is male; one who transitions from female to male.

TRANS GIRL/WOMAN—A person whose biological sex is male, while their gender identity is female; one who transitions from male to female.

UNCONDITIONAL INCLUSION – Inclusion in a category, classification, or group without preconditions, such as including a trans girl/woman in girls’/women’s sport without first requiring her to reduce her male sex-linked advantages.


[1] We use the word “normal” throughout this document consistent with its standard scientific meaning, i.e., the normal range is the range within which almost all readings or levels occur. In medicine, the normal range is sometimes also referred to as the reference range.