We have people bringing us animal bones, thinking they’re human. And I’ve had times when I’ve been faced with a graveful of bones and I’ve had to work out how many individuals there were.

Don't you know I wanna boogie with you / Hey, I wanna boogie with you / Down on the corner

Chorionic villus samples typically contain a mixture of placental villi and maternally derived decidua. Although specimens are thoroughly washed and inspected under a microscope after collection, some maternal cells may remain and grow in the culture. As a result, two cell lines, one fetal and the other maternal, may be identified. In other cases, the maternal cell line may completely overgrow the culture, thereby leading to diagnostic errors, including incorrect sex determination, and potentially to false-negative diagnoses, although there are no published reports of the latter.

Teachers, senior teachers, and principal teachers would have built-in status and the scales would offer well-defined career prospects instead of the ambiguous and often misleading snakes-and-ladders situation which at present exists.