Semenya's sex test explained
This must be an awful time for Caster Semenya, brought up as a girl and a woman, but now facing the possibility of being told she may not be who she thinks she is.
The IAAF has to leave the potential psychological effects of this to one side for now and let the scientists deliver their verdict on the 18-year-old South African who came from nowhere to become World 800m champion.
Gender testing is a complicated business. Basically, if questions are raised there are four main elements to consider: anatomy, physiology, chromosomal makeup and genetic composition.
Those who think it's a simple case of a naked parade, as was the norm when gender testing first happened in sport in the 1960s, are much mistaken, but anatomy is the obvious starting point.
Thankfully, the IOC was persuaded to quickly move on from the crude, unsatisfactory methods first used. Chromosome testing was the next step, and that produces an analysis that is accurate in most cases.
If you present with a XX chromatic profile, you are a woman; XY and you are a man. Easy?
Well, fairly, but how then do explain the example of a woman with secondary sexual development (breasts), anatomically female genitalia, yet with an XY chromosomic presentation? It does happen.
Called the SRY gene, it's the instigator of male foetal development. Where it does its job properly, the male hormones ping off and the male foetus develops normally.
However, in a very small number of cases (perhaps one in 20,000 I understand), there's a malfunction and both female and male genitalia develop, albeit internally, and male hormones like testosterone, are largely held in check.
For sports governing bodies like the IOC or IAAF, where fair competition on the basis of gender is a pre-requisite, this has been a real headache. How and who should decide in these cases whether the person be considered a woman or a man?
The answer is through debate, case-by-case discussion, and a lot of analysis.
The IOC has concluded that people who present with the CAIS syndrome should be considered to be female, but there are variations along the way - and of course we don't yet know the full details of Semenya's case.
All this will have to be gone through, but hopefully more privately than has been the case in Berlin this week.
The South African teenager ought to be shown more sensitivity than was afforded to the Indian runner Santhi Soundarajan (pictured above), who attempted suicide in 2007 after failing gender tests and being stripped of the silver medal she won in the 800m at the 2006 Asian Games.
She survived that ordeal and has now set up her own athletics academy in India, so her story at least had a happy ending.
It's to be hoped Semenya's will too, whatever the outcome of the gender tests she must now be anxiously awaiting.