A gender verification test on the South African athlete, Caster Semenya, has raised sufficient doubt about whether she is entirely female that the results are to be given to a panel of independent experts for further examination.

The 19-year-old South African has not raced since winning gold in the women’s 800 metres at last summer’s world championships in Berlin.

A review due to be published in the June Issue of the International Journal of Sports Physiology and Performance (IJSPP) by Ross Tucker and Malcolm Collins from the University of Cape Town, provides a timely look at the historical context of the debate and aims to discuss relevant physiological and performance aspects of the sex verification process.

According to Tucker and Collins, the division of athletes into male and female categories for competition is a widely accepted practice and is ordinarily straightforward, requiring no intervention from authorities.

However, for reasons ranging from deliberate cheating to complex medical conditions resulting in ambiguous development of sex organs, the controversy of sex verification in athletic events has existed for 70 years.

Testing procedures, initially implemented to prevent cheating by men masquerading as women, continue to have humiliating outcomes for some women athletes who, for the first time and in the full glare of sports media, confront the possibility that their sex development was anomalous.

Sporting authorities have and continue to formulate position stands for the management of such cases. An important missing component in this debate is the sound scientific evidence to determine whether a performance advantage actually exists and if so how large it might be.

To understand the complexity of current sex verification policies it is useful to examine the historical development of testing methods as the background to explain the complexity and genesis of some of the conditions that produce ambiguity in sex development.

It took until the 1960s for widespread concerns over this purported form of cheating to see the introduction of the first measures to screen athletes to ensure their eligibility as females.

In the absence of more sophisticated tests and an understanding of the complexities of sex development, the initial testing procedure consisted of a parade by all female competitors, in the nude, before a panel of judges.

As can be imagined, this so-called nude parade generated substantial resentment and would be replaced by more sophisticated techniques over the course of the next decade.

Apart from the resentment and embarrassment caused to the athletes, the risk of incorrect evaluations was also high because various conditions exist that affect the development of the sexual characteristics.

These screening processes did influence participation in female events, however. The Press sisters of the Soviet Union, Irina and Tamara, had combined to win ten medals at Olympic and European Championships between 1960 and 1966.

However, the introduction of compulsory physical screening saw their immediate retirement from all athletic competition, amid widespread allegations that they were men masquerading as women..

A significant problem with the early testing is that of false-negatives and false-positives, which can be produced as a result of a number of physiological conditions that affect sex development.

Collectively, these conditions have been termed disorders of sex development (DSDs) and they are defined as a spectrum of conditions ranging from those with ambiguous external genitalia to those with normal female appearance, but varying degrees of internal abnormality.

To understand the impact of these DSDs on the testing process of athletes, it is important to understand the basic process of sex development.

The first steps of sexual development , or differentiation, take place in the embryo as early as 5 weeks, when the presence of genes on the X- and Y-chromosomes directs development.

When two X-chromosomes are present and the Y-chromosome is absent, ovaries are developed, with the resultant female development.
When the Y-chromosome is present, testes develop, which produce testosterone and other male hormones, which ultimately result in the development of male reproductive organs.

Testosterone and other androgens such as dihydrotestosterone are responsible for the development of both primary and secondary sexual characteristics.

The primary sexual characteristics are those involving the development of the reproductive organs, while secondary sexual characteristics in males include deepening of the voice, hair growth on face, chest and underarms and increased skeletal muscle mass,

It is this last characteristic that is linked with athletic advantages experienced by male competitors over females.

In a condition known as α-5-reductase deficiency, individuals fail to develop male characteristics and are often raised as girls and it is only at puberty that their musculature develops owing to a return to normal levels of testosterone.

A final common condition among the DSDs identified is congenital adrenal hyperplasia, in which the adrenal glands produce excessive amounts of testosterone in females who go on to develop secondary male characteristics.

In all cases, the individual may present as a female, however, they would also develop male characteristics as a result of the androgen effects of the DSD, but the question remains as to whether these conditions would also confer performance advantages on individuals who have them.

Theoretically, these androgen effects could confer large performance advantages to these individuals, since testosterone stimulates muscle development and resultant speed, strength, power and endurance.

However, no evidence has yet documented whether this theory is borne out, although this is further complicated by the fact that these DSDs are likely to occur to varying degrees and in a relatively small proportion of the population.

The result is that definitive answers as to whether these conditions may provide a performance advantage remain elusive.

It also leaves unanswered the difficult question of whether athletes with DSDs should compete as females when they may possess a performance advantage over other female athletes.

Sport-governing bodies thus find themselves in a difficult position. They had rightly identified that compulsory laboratory testing, established to catch cheats, had never done so and instead humiliated a number of female athletes who were banned from competing, perhaps unjustly.

However, the governing bodies also have the responsibility of ensuring equality of competition for all athletes within the two established competitive categories, i.e., male and female.

This forces authorities to confront the very difficult question of what to do about individuals with a DSD, who blur the simple distinction between males and females and who may possess a performance advantage.

Meanwhile the unfortunate Caster Semenya is left to ponder an athletic future that just a few months ago looked so bright but is now clouded in uncertainty and embarrassment.

“The Science of Sex Verification and Athletic Performance” is soon to be published in the June issue of International Journal of Sports Physiology and Performance (IJSPP).

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