Athletes wishing to compete in the women's category at September's World Championships must take a test to prove they are biologically female. Track and field stars, including Britain's Olympic champion Keely Hodgkinson, will be required to take a 'once-in-a-lifetime' test for the SRY gene, which will be conducted via a cheek swab or blood test. If athletes refuse to take the test or test positive for the Y (male) chromosome, they will not be allowed to compete in the female category at future competitions. The new rules will be applied ahead of the World Championships in Tokyo, which begins on September 13, with athletes required to have completed the test before the closing date for entries on September 1. World Athletics banned transgender women from competing in the female category at international events two years ago, but the new test further tightens their regulations. The move follows the controversy in the women's boxing at last summer's Paris Olympics, when Imane Khelif and Lin Yu-ting won golds despite being disqualified from the previous year's World Championships for failing gender eligibility tests. 'The philosophy that we hold dear in World Athletics is the protection and the promotion of the integrity of women's sport,' said World Athletics president Lord Coe. 'It is really important in a sport that is permanently trying to attract more women that they enter a sport believing there is no biological glass ceiling. The test to confirm biological sex is a very important step in ensuring this is the case. 'We are saying, at elite level, for you to compete in the female category, you have to be biologically female. It was always very clear to me and the World Athletics Council that gender cannot trump biology.' World Athletics have warned athletes to get tested 'as soon as possible', as it can take up to two weeks for cheek swap or blood samples to be analysed and the results issued. Member federations will carry out the tests of their own athletes, but the global governing body will contribute up to £75 per test for those competing in Tokyo. The SRY gene is seen as a 'reliable proxy for determining biological sex' and the test is said to be 'extremely accurate' with the risk of false negatives or positives 'extremely unlikely'.