The Court of Arbitration for Sport (CAS) said yesterday it had opened a probe into Caster Semenya's challenge of controversial new IAAF rules on testosterone occurring in female athletes.

CAS said it had "registered a request for arbitration" filed by the South African two-time Olympic gold medallist against the "International Association of Athletics Federations' (IAAF) 'Eligibility Regulations for Female Classification (Athletes with Differences of Sex Development)' that are due to come into effect on 1 November 2018".