The inability of 400m hurdler Sanique Walker to undergo the recently introduced once-in-a-lifetime test for the SRY gene, a reliable proxy for determining biological sex, has cost her the chance to replace the injured Rushell Clayton on Jamaica's team at the Tokyo World Championships.

Manager of Jamaica team, Ian Forbes, made the revelation in an interview with Radio Jamaica Sports Reporter Jeremain Brown in Tokyo. The new regulations (C3.3A and C3.5A in the World Athletics Library) came into effect on September 1, 2025 and will be applied to the World Athletics Championships Tokyo 25 that begins on September 13.