So quick she's become a blur

AT FIRST they thought she must be on steroids. Surely there could be no other explanation for such a suspiciously stellar rise in performance, one that saw her knock more than 16.5 seconds off her time from the same meeting a year before? But then a routine drugs test dispelled that notion, and deepened the mystery of the girl who had come from nowhere.

This time last month Caster Semenya, a little-known 18-year-old South African from the remote village of Ga-Masehlong north of Pretoria, was an international no-mark, an athlete of little or no significance. But within the space of three weeks and with two performances of preternatural brilliance she rocketed to the top of the sporting agenda. In doing so, she placed herself in the limelight, her notoriety even vying for column inches with Usain Bolt's historic double.

Like Bolt, Semenya left the opposition looking like they were running in concrete wellies. The young African left defending world championship 800m title-holder Janeth Jepkosgei trailing by almost two and a half seconds with a time of 1min 55.45sec – three-quarters of a second faster than Kelly Holmes' lifetime best.

And then there's the physique. You'd expect that frame from Bolt, but the taut, bulging biceps which Semenya displayed as she posed in front of her record-breaking time were a provocation for her vanquished opponents.

After she won the African Junior Championships in Mauritius three weeks ago in the staggeringly quick time of 1min 56.72sec, it hadn't taken long for the gossips to get busy. When Semenya arrived in Berlin for the world championship 800m heats, the rumour mill was in full flow; the other girls watched her warm-up with undisguised scepticism. As her dominance increased, so did the murmurs that she wasn't all she seemed. By the time she climbed on to the podium to collect her gold medal, the IAAF had asked her to undergo a gender test.

The great and the good of athletics, men like Michael Johnson and women like Denise Lewis, complained at the humiliation being heaped on Semenya, while South Africa reacted with a fury. Yet, with the IAAF test results not yet in, could the mannish, flat-chested, super-powerful Semenya really be one of the boys?

It's not an outlandish question. Down the years there have been plenty of male athletes masquerading as women. Pentathlete Mary Rand was denied a gold medal in 1964 by the Ukrainian athlete Irina Press, only for Press and her sister Tamara, who between them won five Olympic gold medals, to mysteriously disappear in 1968 when gender testing was introduced.

At the 1936 Berlin Olympics, Germany was so desperate for medals that several "female" athletes were highly suspect. One, Hitler Youth member Hermann Ratjen, entered the women's high jump as Dora Ratjen and came fourth. "I knew Dora was a man, you could tell by the voice and the build," said British silver medallist Dorothy Tyler. "But 'she' was far from the only athlete. You could tell because they would go into the toilet to change. We'd go and stand on the seat of the next cubicle or look under the door to see if we could catch them."

Another mannish competitor at that Olympics was Stella Walsh, an American-Polish sprinter who won gold at the 100m in 1932 and silver in 1936. By the time she was inducted into the American Track and Field Hall of Fame in 1975 she had set more than 100 national and world records, and had been married. Yet when she was shot dead during a bungled robbery in Ohio in 1980, it transpired that she had male genitalia.

That, however, didn't make her a man. Walsh suffered from mosaicism, a genetic condition in which cells within the same person have a different genetic makeup, and was in every respect a woman. Mosaicism is just one of several conditions that can affect female athletes. Congenital adrenal hyperplasia is another, where a woman has normal internal female reproductive organs despite her body producing an excess of the male hormone androgen, resulting in a male appearance and lack of periods.

In androgen insensitivity syndrome, someone may have internal and undescended testes, and high levels of testosterone, yet look like a woman and have a vagina and uterus. This is reported to be the reason why Indian 800m runner Santhi Soundarajan failed a gender test after winning a silver medal at the 2006 Asian Games. Soundarajan, whose case has yet to reach a conclusion, was so humiliated that she withdrew from sport and reportedly tried to take her own life.

As well as such hormonal imbalances, there are various other ways in which gender differences can be muddied. Women are supposed to have two X chromosomes while men have one X and one Y chromosone, yet around one in 1,000 babies are born with an "intersex" chromosomal abnormality in which that is not the case. Because that abnormality can cause higher testosterone readings, giving women up to 20 per cent greater strength, the incidence of often undiagnosed "intersex" conditions among top athletes is higher than one in 1,000.

At the 1992 Barcelona Olympics, five women failed the gender test; while at Atlanta in 1996, the last at which gender testing was mandatory, eight females failed tests only to be cleared on appeal, which was why the test was abandoned for Sydney.

Nor is a simple physical examination sufficient. The IOC's medical team says that the clitoris may be so enlarged that it resembles a penis, while the labia can become fused and resemble a scrotum. Even the common hormonal disorder polycystic ovary syndrome, which affects 5 per cent of all women, can lead to excess testosterone and can manifest itself in more facial hair.

All of which perhaps explains why the IAAF has described the three-stage process of verifying gender as "an extremely complex procedure" which involves a gynaecologist, endocrinologist, psychologist and a genetic expert.

There have been numerous cases of hermaphrodite women born with both male and female sexual organs, yet their opponents have not always been welcoming. Brazilian judoka Edinanci Silva had surgery in the mid-90s so that she could compete, but when she beat Natalie Jenkins in Sydney, the Australian constantly referred to Silva as "he". Similarly, Sarah Gronert, a 22-year-old German tennis player who underwent the same surgery as Silva, has attracted criticism because of the belief that, while a woman, excess testosterone makes her unusually powerful. "There is no girl who can hit serves like that, not even Venus Williams," said coach Schlomo Tzoref, whose charge Julia Glushko was recently beaten by Gronert. "I don't know if it's fair that she can compete."

In Zimbabwe in 2005, the country's most successful athlete, 18-year-old Samukeliso Sithole, was charged with impersonating a woman because she "possessed a male organ". Yet when the pretty Zimbabwean junior long jump, high jump, 400m hurdles, javelin and shot champion turned up at court with her boyfriend and wearing a fetching dress, the prosecution admitted that "the court has a problem (because] she has everything of a woman – breasts, voice, features."

This is an issue that is sure to keep raising its head. At last year's Beijing Olympics the Chinese installed a laboratory where the blood and chromosomes of "suspect" athletes could be checked, and gender tests will feature in 2012. The Olympics' inclusion of transsexuals who have made the transition from manhood to femininity, as long as they wait two years after the operation, is also sure to raise many of the issues faced by tennis when Renee Richards (formerly journeyman pro Richard Raskin) reached the quarter-finals of the US Open in 1978, when golfing transsexual Mianne Bagger entered the Australian Open in 2004 or mountain-biker Michelle Dumaresq secured a top-25 finish in the 1996 World Championships after a sex change.

Yet for Semenya, a teenager who has been brought up as a girl and was so upset by the publicity that she considered boycotting the medal ceremony, all of that is in the future. Even if she passes the gender test, it will have been such a bruising success that hers will be the most unsatisfactory, pyrrhic victory.