Scientists worldwide are attempting to develop a laboratory-made version of the rarest blood type, Rh-null, often called 'Golden Blood'. Found in only about one in six million people, this blood lacks all 50 known Rh antigens, making it compatible with nearly all Rh blood groups. Due to its extreme rarity—only around 50 people globally have it—researchers are exploring genetic and stem cell technologies to replicate it. Teams in the UK, Canada, the US, and Spain are using CRISPR-Cas9 gene editing and stem cell methods to produce customized red blood cells. Although large-scale production remains challenging due to cell maturation and technical hurdles, clinical trials like the UK’s RESTORE project have begun testing lab-grown blood in humans. Experts believe that while traditional donors will still be needed, lab-produced rare blood could revolutionize transfusion medicine and save lives in the future.