In humans, sickle-cell anemia is an example of co-dominance, when considered at the molecular level. People who are homozygous dominant produce all normal-shaped hemoglobin molecules. Hemoglobin is a protein found in red blood cells that carries oxygen. People who are homozygous recessive produce all abnormally-shaped hemoglobin, which cannot carry oxygen very well. People who are heterozygotes produce some normal and some abnormal hemoglobin. If a person who is homozygous dominant for this allele produces children with someone who is heterozygous, will any of their children produce only abnormal hemoglobin? What percentage of their offspring will be homozygous versus heterozygous?