Caster Semenya's discrimination case has been referred to the Grand Chamber of the European Court of Human Rights (ECHR) for a final ruling.
Semenya has been unable to compete at her favoured distance of 800 metres since 2019, following the introduction of limits on testosterone levels for female athletes by World Athletics.
The 32-year-old South African, who won Olympic gold over 800 metres in 2012 and 2016, was legally identified as female at birth but has a condition which means her body naturally produces higher levels of testosterone than women without the condition.
Earlier legal challenges by Semenya at the Court of Arbitration for Sport (CAS) and the Swiss Federal Court had been rejected, but an ECHR decision in July found her human rights had been violated by the Swiss government.
The court found by a majority of four to three that the Swiss government had not afforded her "sufficient institutional and procedural safeguards" to allow her to have her complaints examined effectively.
The Swiss government requested the case be referred to the ECHR's Grand Chamber, and the court confirmed on Monday that the request had been accepted.
The initial court ruling in July said the "high stakes" involved for Semenya "should have led to a thorough institutional and procedural review".
Semenya had been unable to obtain such a review, therefore the ECHR was "unable to determine whether the DSD (Difference in Sex Development) regulations, as applied in the applicant's case, could be considered a measure that was objective and proportionate to the aim pursued (of protecting fair competition for female athletes)".
It said her complaints of discrimination as a result of World Athletics' regulations were "substantiated and credible" but the judgement did not bring into question the DSD regulations themselves, nor did it allow Semenya to compete over 800 metres.
Semenya told CNN this month that taking medication to lower her testosterone had been "hell" and had caused a number of health issues.
World Athletics had stated in July that it would encourage the Swiss government to refer the matter to the Grand Chamber, and said its regulations were "a necessary, reasonable and proportionate means of protecting fair competition in the female category".
A spokesperson for World Athletics said on Monday evening: "This is a matter between the Swiss Government and the ECHR but we stand ready to provide any information that will help provide clarity and context as we have done in the past."