New rules to reduce naturally high testosterone levels in female athletes have been branded “unscientific”.
Last year, athletics chiefs ruled women with levels of five nanomoles per litre or more must have hormone treatment before being allowed to compete.
But medical experts, reporting in the BMJ, say there is a lack of evidence about testosterone’s effects and the cut-off figure is arbitrary.
A decision on the legality of the rules is expected later this month.
The International Association of Athletics Federations (IAAF) delayed implementing its regulations after South African runner Caster Semenya contested the legality of the new rules.
She was banned from international competitions for nearly a year for having testosterone levels above the athletics body’s limit for female athletes.
World athletics bosses have previously said they want to protect