Rh-negative refers to the absence of the Rhesus factor, a specific protein found on the surface of red blood cells. People with Rh-negative blood do not have this protein, while those with Rh-positive blood do. The Rh factor is important in blood transfusions and pregnancy, as incompatibility can lead to serious health issues. Approximately 15% of the global population is Rh-negative, with varying prevalence among different ethnic groups. For example, Caucasians have a higher percentage of Rh-negative individuals compared to Asians and Africans. Understanding Rh-negative status is crucial for safe medical practices and blood donation.