Sickle cell anaemia is a recessive disorder in which the blood of the person is not able to clot properly. For sickle cell to occur, both the alleles for the trait have to be recessive. A person who has a dominant and a recessive allele will be heterozygous, showing the dominant characteristics. But such a person will be a carrier for the disease. There will be chances for the offsprings of that person to actually have the disease.
