I think this needs to posted - and re-posted from time to time. There are some horror stories about families who didn't know about this, and the consequences they have suffered:
As of 1 October 2014 all persons under the age of 18 entering or leaving South Africa will be required to have, besides a passport, an Unabridged Birth Certificate. This type of Birth Certificate must contain the names of both parents. An English translation is NOT required.