All athletes wishing to compete in the female category at the World Championships are required to take the test
Rules requiring all athletes in the female category of world ranking events to take a one-time gene test come into force this week.
World Athletics says the sex screening - which detects the presence of a Y chromosome - is to protect the integrity of women's competition.
But how does the latest attempt to tackle one of sport's most contentious issues work? How did we get here, are there concerns, and what are the implications for the debate around gender eligibility? BBC Sport answers the key questions.
The test detects the SRY gene - or 'sex-determining region Y gene' - which is part of the Y chromosome and causes male characteristics to develop.
