Sickle cell trait means having one gene for a condition called sickle cell disease (SCD). This in itself does not normally cause problems and sickle cell trait is not considered as a disease. It is extremely rare for it to cause problems or complications, which mainly occur under conditions of severe physical stress (explained below).
This is a companion discussion topic for the original article at https://patient.info/allergies-blood-immune/sickle-cell-disease-sickle-cell-anaemia/sickle-cell-trait