July 4 - The International Association of Athletics Federations (IAAF) has denied claims that four unnamed athletes who competed as females at the London 2012 Olympics were found to have the genetic makeup of males.
A report on the International Business Times website said the competitors had the XY chromosomes, which genetically define men, rather than the female XX and had their testes removed surgically in order to appear at last summer's Games.
"The surgeons have neutered these individuals," a consultant from London Bridge Hospital is reported to have said.
"They have castrated them by removing the gonads, by which I mean their male testes, and they've had gender reassignment surgery.
"You could do that to any man."
However, the IAAF has told insidethegames that "not one athlete was investigated at London 2012 and found to have had hyperandrogenism" - a medical condition characterised by the excessive production of androgens/testosterone which affects one in every 4,500 people.
Issues surrounding gender verification in sports have raised a catalogue of issues in the past.
The most famous case is that of Poland's Stanisława Walasiewicz (pictured top) – also known as Stella Walsh, who won the women's 100 metres at the Los Angeles 1932 Olympics but was found to have "ambiguous genitalia" when she was shot dead years later in a robbery.
The 1960s saw the case of the Press sisters - shot putter and discus thrower Tamara and pentathlete Irina, who collectively won five gold medals at Rome 1960 and Tokyo 1964 for the Soviet Union but both were accused of being men.
Both sisters left the international sporting scene before gender verification became mandatory in 1966.
The practice came under fire and the International Olympic Committee (IOC) passed a resolution "to discontinue the current process of gender verification during the Olympic Games" at its 1996 World Conference on Women and Health, but the IOC still holds the right to test on gender.
Most recently, Indian middle distance runner Santhi Soundarajan was stripped of the silver medal she won in the 800m at the 2006 Asian Games after failing a gender verification test, while South African Caster Semenya ignited controversy following her 2009 World Championships victory in the 800m and was subjected to gender testing before being cleared to return to competition.
Although Semenya went on to win the 800m silver at London 2012, her case sparked considerable reaction which saw sports officials, lead by IOC Medical Commission chairman Arne Ljungqvist, introducing guidelines on how to deal with athletes with ambiguous sexual characteristics.
The IAAF itself introduced new edibility rules, which were formulated in close cooperation with the IOC, in May 2011, which say that a female with hyperandrogenism is eligible to compete in women's competition provided that her androgen levels - measured by testosterone level- are below the male range.
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April 2011: IAAF introduce new gender rules for female competitors
April 2011: IOC introduce guidelines to avoid repeat of Semenya fiasco
January 2011: Semenya unfazed by gender hullabaloo
November 2010: IAAF to issue guidelines on gender to avoid repeat of Semenya debacle
September 2010: South African Parliament calls Caster Semenya "mister" in official report