Female athletes who naturally produce high levels of testosterone,
comparable to those of males, may not be eligible to
compete with other women in sporting events, according to the
International Association of Athletics Federations.
The International Olympic Committee recommended the new guidelines April 5, with the IAAF accepting the recommendations a week later, according to the journal Nature. The IOC has not yet determined the maximum hormone level for an eligible female athlete, but premenopausal women usually produce 15-70 nanograms of testosterone per deciliter of blood, compared with 260-1,000 nanograms per deciliter for a man.
The condition in which women have higher-than-normal levels of androgens (male hormones), particularly testosterone, is known as hyperandrogenism However, women who have extreme hyperandrogenism but lack a fully functioning testosterone receptor would not be affected by the ban. Nor would females with testosterone levels that are higher than most women's but still not as high as a typical male's levels.
Though officials deny the guidelines are linked to the controversy over South African track and field athlete Caster Semenya, the runner was barred from competition for a year after blood testing showed unusually high androgen levels.