Here is some more about the inclusion of males in female sports categories from David Handelsman
From David Handelsman
5th April 2024
https://academic.oup.com/edrv/advance-article/doi/10.1210/endrev/bnae013/7641481?login=false
There is a good diagram showing the stages of genital development and 5ARD & CAIS here as well.
Essential Points
“A definition of the term sport sex is proposed based on an individual's experience of male puberty integrating related physiological factors such as male birth sex, the presence of a testis, and adult male circulating testosterone levels.“
“Male puberty involves a 20- to 30-fold increase in testosterone production over that prevailing in children and women at any age, creating the postpubertal male physical advantages of sex differences in athletic performance through the androgen-dependent uplift forming larger and stronger muscles and bone, more powerful cardiorespiratory function, and higher hemoglobin.“
“Physiological mechanisms of the sex differences in performance may involve muscle memory and the effects of neonatal minipuberty, but alternative explanations claiming effects of GH or an unspecified Y chromosome gene are not credible.“
“While many genetic factors contribute to sporting success, the genetic mutations creating 46XY DSDs defeat the sex classification of sport and are incompatible with fair play in elite individual competitions for the vast majority of non-DSD, non-transgender females. The degree to which sustained complete testosterone suppression eliminates the legacy advantages of male puberty remains uncertain and difficult to evaluate decisively.“
“As a result, traditionally elite individual sports where success depends on power, speed, or endurance are classified into male and female events aiming to create a protected female category allowing women to achieve fame and fortune from success that competing against men would deny.“
“Participation in elite female sports of unmodified transgender (male-to-female) women or 46XY disorders of sexual differentiation in elite female events represents male-bodied athletes using unfair postpubertal physical advantages and is category-defeating for the binary sex classification of sport.“
“Recreational, community, and junior (<12 years old) sports, as well as sports not reliant on physical prowess, may not need a sex classification based on male physical advantages and could operate fairly with an open category.“
“The optimal management in team sport participation of transgender and 46XY DSD individuals is a complex and still unresolved issue depending on the relevant team skills and contribution of any single individual to team success.“
Why males with DSDs where there is virilisation and those males with transgender identities should be considered the same. Ie. Males with DSDs where there is virilisations is not a ‘different issue’ at all as some people claim. Those claims are then used as a silencing tactic.
“These physiological issues of the 46 XY DSD individuals have important ramifications for male-to-female (M2F) transgender individuals in relation to elite sports competition. While neither condition involves deliberate cheating, when unmodified by any testosterone suppressive treatment after completing a male puberty, they both provide the same unfair male physical advantage over all other female athletes as would a non-transgender, non-DSD male.”
An interesting insight into why ‘gender’ is not useful for sports categories.
“The subjective nature of gender identity, which can only be verified by asking the individual, with its potential for volitional change at any time, means that no fixed, invariant gender can be ascribed to individuals. As such, gender cannot form a sound durable objective basis for defining sport sex. Hence, a previous proposal to define “athletic gender” as a means to stratify elite athletic events would be unable to provide consistent objective classifications over different times or events including even within the same competition.”
Interesting point on the hypothesis of muscle memory
“An important amplifier of androgen effects on muscle is the concept of muscle memory arising from the innovative experiments of Gundersen. He first showed in rodents that myonuclei created during androgen- or exercise-induced muscle hypertrophy are not lost when the androgen or exercise stimulus is withdrawn. Furthermore, the residual expanded pool of myonuclei enhance muscle functional responses to subsequent training or androgen exposure. This makes the permanence of myonuclear expansion a pivotal factor in the muscle memory mechanism with relevance to short-term androgen doping and longer-term androgen exposure in individuals who are transgender and XY DSD. Nevertheless, achieving proof (or refutation) of this concept in humans is a formidable challenge due to the practical constraints on decisive but ethical human investigation.”
And
“Ultimately, further rigorous evidence is required to confirm this important hypothesis in humans. If true in humans, the muscle memory hypothesis has many important implications. By explaining the durable uplift in muscle function arising from the dramatic increase in circulating testosterone during male puberty, it forms a key contribution to the sex difference in athletic performance. It also suggests that androgen doping may have lasting effects for many years, if not indefinitely, thereby raising questions about the adequacy of the present maximum 4-year suspension period for androgen doping under the WADA Code.”
And
“Finally, if this mechanism is confirmed in humans, testosterone effects on muscle memory among those who have completed male puberty casts doubt over whether transgender women or androgen-sensitive 46XY DSD individuals could compete fairly in elite female events.”