Cord blood is the blood that remains in the umbilical cord and placenta after a baby is born. This blood is rich in stem cells, which are special cells that can develop into different types of blood cells and have the potential to treat various medical conditions. Many parents choose to collect and store cord blood for future use, a process known as cord blood banking. This stored blood can be used in medical treatments for diseases like leukemia and certain genetic disorders, making it a valuable resource for families and medical research.