Given the question: Given the following passage  "Many Pygmies belong from birth to Bantus in a relationship many refer to as slavery. The Congolese Human Rights Observatory says that the Pygmies are treated as property the same way "pets" are. On December 30, 2010, the Congolese parliament adopted a law for the promotion and protection of the rights of indigenous peoples. This law is the first of its kind in Africa, and its adoption is a historic development for indigenous peoples on the continent.",  answer the following question. Note that the answer is present within the text.  Question: When do Pygmies become slaves?
The answer is:
birth