World Athletics, the global governing body for athletics, has approved the introduction of a new genetic test to determine the biological sex for athletes wishing to compete in the female category.
The new regulation will come into effect on 1 September 2025, before the World Athletics Championships in Tokyo.
The Sry gene is part of the Y chromosome, and is necessary for the development of testes. If the Sry gene is absent, the fetal gonads develop into ovaries, even if a Y chromosome is present.
The test can be conducted via a cheek swab or blood test and only needs to be taken once in a lifetime.
BBC News has more on this story.