In an effort to address questions about fair play, track and field’s world governing body will publish regulations on Thursday that could force some elite female athletes with naturally elevated testosterone levels to lower the hormone with medication, compete against men in certain Olympic events or effectively give up their international careers.

The rules, scheduled to take effect in November, will initially be enforced in middle distance races of 400 meters to 1 mile. These distances, which synthesize the need for speed, power and endurance, are events in which raised testosterone levels can have the most profound influence on performances, the sport’s top officials say.

The regulations are certain to cause further controversy and perhaps bring another legal challenge to the most elemental of sports, in which competition is divided into male and female categories, while biological sex is not nearly so neat and binary. Track and field has gone through contortions on this issue for years, most visibly regarding Caster Semenya of South Africa, a dominant middle distance runner and two-time Olympic champion at 800 meters.

— The New York Times