Is gender an absolute M/F category?

South African athlete Caster Semenya is being scrutinized to determine whether she is "truly" a woman.

Semenya, a newcomer to high level competition, blew away her rivals with a dominant run in last night's track final in Berlin, but was already aware that she may have to return her gold medal if she fails a gender verification test.

Comments after the race from her beaten rivals emphasised the unpleasant situation in which she now finds herself. Russian Mariya Savinova, who came fifth, questioned Semenya's gender while Italy's Elisa Piccione, who finished sixth, was more damning. “For me, she is not a woman,” she said.

More about this.

How many forms have you completed that had two boxes - one male, the other female - for which you had to tick only one?

Post-birth the bodies of every human being at various stages of their development can produce female and male hormones - even though the blastocyte which can be affected by the hormones produced by pregnant women during the course of its development is either XX or XY.

But like the official forms that need to be completed when every baby is born, there are social and cultural institutions that require un-ambiguous categories. Such as sports competitions.

Olympic trivia: Anne the Princess Royal, only daughter of Elizabeth II, was not was obliged to submit to gender-testing when she competed in the 1976 Montreal Games.