The runner-up behind Semenya was another South African notable -- double-amputee runner Oscar Pistorius. But the South African Olympic committee worried that choosing Pistorius would lead to "other theories" and called Semenya the "ideal choice."
We last heard from Semenya in 2009, following her World Championship win in the 800-meter race. The International Association of Athletics Federations (IAAF) requested both drug and gender verification tests, citing the 18-year-old's bulging muscles and rapid time improvements.
[ Photos: South African runner Caster Semenya ]
The controversial test involved physical, gynecological, and chromosomal examinations. Critics labeled the investigation overly intrusive, humiliating and racist; and South Africans rallied behind Semenya. In a long-overdue tasteful move, the test results were kept private. And after an 11-month ban from racing, Semenya was permitted to keep her World Championship gold medal, cleared of any "wrongdoing," and allowed "to decide her future on her own."
Semenya and her family say that she is indeed female, and she will run as such in London. Despite struggling with injuries and finishing second in last year's World Championship, she's a favorite to win gold.
Other popular Olympics content on Yahoo! Sports:
• Michael Johnson opens mouth again, calls out Oscar Pistorius
• Malaysia's first female shooter will compete eight months pregnant
• Photos: Inspirational Olympic moments
- Sports & Recreation