 Complete the following phrase:  The three 2016 Olympic medallists in the womens 800 metres were all excluded from the 2019 World Athletics Championships under the IAAFs testosterone rules. Caster Semenya, Francine Niyonsaba and Margaret Wambui all acknowledged they had a difference in sex development DSD which resulted in their bodies producing levels of testosterone above the limits set by the IAAF for womens competition. The IAAF rules stipulate such athletes must take testosterone-reducing medication in order to compete in womens races. Caster Semenyas appeal to the Court of Arbitration for Sport CAS against this rule was ongoing at the time of the World Championships. All three athletes declined to adhere to the IAAFs ruling and thus could not compete. CAS had previously made a decision in May 2019 to uphold the IAAFs rules on the grounds that they were discriminatory to athletes with a DSD, but that discriminatory action was a necessary, reasonable and proportionate means of achieving the legitimate objective of ensuring fair competition in female athletics. Kenyan athletes, 800 m national champion Jackline Wambui and Linda Kageha, who was in the mixed relay team, were excluded from selection for Kenya as they refused to submit to a testosterone test. Because of the testosterone rule, 400 metres world No. 3 Aminatou Seyni competed in the 