A better-known example of this kind of historically influenced antagonistic pleiotropy is sickle cell disease in which homozygotes for the Hb-S allele have poor life expectancies due to blood cell malformations, but heterozygotes for the Hb-S allele have increased resistance to malaria during early childhood (Aidoo et al., 2002). This evidence concerns the gene GSTM1 and malaria.