Stem cells are one of the most important discoveries in modern medicine, as they have the ability to transform into any other type of cell in the body, such as heart, liver, or nerve cells. This property makes them a powerful tool for developing treatments for diseases that were once considered difficult or untreatable, such as spinal cord injuries, sickle cell anemia, and certain cancers. Stem cells are used in regenerative medicine to repair and replace damaged tissues with healthy cells. They are also used to develop disease models in the lab to better understand illnesses and discover new drugs. Moreover, stem cell research allows for the design of personalized treatments tailored to the genetic makeup of each patient. Despite these benefits, the use of stem cells raises ethical concerns, especially regarding embryonic stem cells. Therefore, medical institutions follow strict regulations to ensure responsible use of this technology, while ongoing research continues to expand understanding and potential applications.