Female track athletes with elevated levels of testosterone, a condition known as hyperandrogenism, will be required to lower the amount of the hormone circulating in their blood for six months before being allowed to compete from the quarter-mile to the mile in major global events like the Olympics and the world championships.
"We have a responsibility to ensure a level playing field for athletes. where success is determined by talent, dedication and hard work rather than other contributing factors", IAAF president Sebastian Coe said in a statement. "It does not want to risk discouraging those aspirations by having unfair competition conditions that deny athletes a fair opportunity to succeed".
The sports Minister was similarly furious and said the regulations "are created to disadvantage Caster in her career".
"As a federation, we will study the new regulations and compare them with the CAS (Court of Arbitration for Sport) recommendations to see if they are compatible and in line".
Caster Semenya will be forced to keep and maintain her testosterone levels below 5 nanomoles per litre.
The regulations are meant to ensure "fair and meaningful competition within the female classification", according to track's governing body, the International Association of Athletics Federations, known as the IAAF.
Earlier this month‚ Semenya secured a golden double at the Commonwealth Games - winning the 800m and the 1500m titles in Games record times‚ also breaking fellow South African Zola Budd's 34-year-old national mark in the 1500m.
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The new rule is slated to take effect in November and would effect athletes in the 400 meters to mile.
New Zealand weightlifter Laurel Hubbard, whose birth name was Gavin, was granted permission to participate in the women's competitions following her male-to-female gender reassignment surgery.
If female athletes affected by the ruling do not take wish to take the medication, then they will still be allowed to compete in long-distance races, in non-International Competitions in those events now restricted, or in the male classification.
But South Africans rallied behind Semenya and blasted the athletics body.
And the Minister responded later on Thursday by expressing her "dismay" with the IAAF's decision, with the statement saying that the "Caster Semenya Regulations are nothing but a continued attack on the persona of Caster Semenya, the South African Golden girl".
Research over a decade showed 7.1 in every 1,000 elite track and field athletes had elevated testosterone levels - 140 times greater than the female population. The treatment to reduce testosterone levels is a hormone supplement similar to the contraceptive pill taken by millions of women around the world.