text: Ukukhiqizwa kwesidoda – okubuye kwaziwe nge-spermatogenesis – kukhiqiza isidoda esingaphezu kwesingu-1,000 ngomzuzwana kwabesilisa abavamile. Lokhu kukhiqizaa, kokunye, kuvela ohlotsheni olukhethekile lwengqamuzana ekhethekile ebizwa ngokuthi inqamuzana ye-spermatogonial ye-stem. Amandla okuzinza ale ngqamuzana ye-stem asenze abaningi bosaziwayo, kuhlanganise no-Robert DeNiro no-Pablo Picasso bakwazi ukuzalisa sebeve eminyakeni engu-65.  