This all seemed perfectly logical until the invention of the microscope revealed an awkwardness: female genitalia.

ECONOMIST: Bees

The partial or total removal of external female genitalia is illegal in the UK but the practice occurs in parts of Africa, the Middle East and Asia.

BBC: Midwife 'role' as NHS targets female genital mutilation

The opposition accused Ms Gillard's government of hypocrisy for standing by the Speaker after it was revealed that he used "offensive" language to describe female genitalia in text messages.

BBC: Asia

The conditional registration order, in force until October, includes that Dr Scholten must also not undertake consultations with female patients without a chaperone present and refrains from photographing female genitalia without consent.

BBC: Genital photo surgeon Erik Scholten has suspension lifted

However, after she was shot dead during an armed robbery in 1980, the subsequent autopsy revealed she possessed male genitalia, although she also had female characteristics as well.

CNN: Women's world champion Semenya faces gender test