Fetal hemoglobin or foetal hemoglobin is the main oxygen transport protein in the human fetus during the last seven months of development in the uterus and persists in the newborn until roughly 6 months old. Functionally, fetal hemoglobin differs most from adult hemoglobin in that it is able to bind oxygen with greater affinity than the adult form, giving the developing fetus better access to oxygen from the mother’s bloodstream. The results revealed that HbF was highest (98%) at birth, decreasing at 5% per week till 6 months when it wane off. Ten infants aged 6 – 12 months had HbF persisting at a level of 10% or more. Adult patients examined showed proportions of their sickle cell types as forming 51%, AC 20%, SS 19%, and SC 10%. An SS adult patient with mild sickle cell crisis had an ASF father who had no crisis and a mother and brother with AS each who had severe crisis.