Court of Arbitration for Sports (CAS) Secretary-General Matthieu Reeb has dubbed the much-publicized hearing of South African middle-distance runner Caster Semenya as "unprecedented".

While speaking at the CAS headquarters in Lausanne on Monday, Reeb said that the move would not only raise juridical but also ethical and philosophical questions.

South African double Olympic 800meter champion Semenya is challenging at the CAS, the apex court in the world of sports, against the new regulations of the IAAF, the international governing body of track & field, which are aimed at lowering the testosterone levels of "hyperandrogenic" female athletes. “Hyperandrogenism” is a medical condition in which women may have excessive levels of male hormones such as testosterone.

According to the IAAF regulations, women athletes with elevated testosterone should take medication to reduce their level before being allowed to compete, but only in the middle-distance events of between 400- and 1500-meters, where it is claimed the advantage, is most felt.

The South African Athletics Federation has been supporting Semenya, saying that such a rule is a negation of Semenya's basic human rights.

Arriving for the start of the hearing, the president of IAAF Sebastian Coe said that the ruling was only aiming at preserving "fair and open competition."

The hearing is expected to last five days, with witnesses and experts testifying.

Semenya will be heard last and subsequently, a final decision will be rendered by the end of March, after a four-week deliberation.

While speaking to the reporters, Reeb informed, "For the week, it is a succession of evidence, witness, experts, with closing submissions on the last day - Friday - hopefully, the panel will be able to conclude the hearing by Friday night, and then there will be about four-week deliberations between the panel members, and a final word, a final decision will be issued in writing and will be announced publicly."