Sickle cell anemia results from a genetic mutation that affects hemoglobin, the iron-rich protein in red blood cells responsible for transporting oxygen throughout the body. This mutation causes hemoglobin to form abnormally, leading red blood cells to become rigid, sticky, and crescent-shaped, which impairs their ability to carry oxygen efficiently and can block blood flow. For a child to inherit sickle cell anemia, both parents must carry a copy of the sickle cell gene and pass both mutated copies to the child. If only one parent passes on the sickle cell gene, the child will be a carrier (possessing the sickle cell trait). Individuals with the sickle cell trait produce both typical hemoglobin and sickle hemoglobin.