This paper deals with sickle-cell disease (SCD, also known as sickle cell anemia) from a genetic point of view. The disease and its genetic trait do not conform well to the traditional model of genetic inheritance, which required that the medical establishment rethink its ideas about genetic concepts like "dominant" and "recessive". It often occurs in areas rife with malaria, and may be linked to an increased protection from severe malaria. Also discussed: symptoms of SCD, treatments and gene therapies, and demographics. 6 pgs. Bibliography lists 8 sources.