Aperson with a phenotype of hbss has sickle cell disease. a person with a phenotype of hbas allele carries the sickle cell trait. a person with a phenotype of hbaa does not have sickle cell disease and does not carry the trait. the punnett square shows the genotypes of two people carrying the sickle cell trait. hb a s a aa as s as ss what are the chances that their offspring will have sickle cell anemia?