The gender test ordered up for the South African wunderkind who grabbed 800-metre gold this week could reveal any of several genetic disorders resulting in a physically ambiguous sexual identity, experts say.

Hormones and surgery, in other words, are not the only things that can bend gender to boost female performance by shape-shifting bodies and building muscle mass.

But taking steroids or hiding a sex-change is cheating.

Being born with unusual chromosomes is not, which raises the uncomfortable possibility that an athlete could be stripped of a gold medal because of her -- or his -- genes.

Whether this is what lies in store for 18-year-old Caster Semenya, who demolished the competition at the athletics world championships in Berlin, is still unknown.

A spokesman for the sport's governing body, the International Association of Athletics Federations (IAAF), said Thursday that even if she "fails" the gender test she might still be able to keep her title.

But her blistering speed and masculine physique raised doubts about her sexuality, prompting the IAAF -- acting, perhaps, after a challenge from a national federation -- to call for a closer look.

The IAAF has said very little about the tests, but guidelines laid out by its medical committee on gender verification give clues as to how the process will unfold.

"Determination should not be done solely on laboratory-based sex determination" in resolving contested cases, it says.