True. Until the 1990s, identifying the blood type of a sample was indeed the best that forensic scientists could do in terms of linking a blood sample to a particular person. Blood typing, which involves determining the ABO and Rh blood groups, was a common method used in forensic investigations to provide limited information about the potential source of a blood sample. By comparing the blood type of a sample found at a crime scene with the blood type of a suspect or victim, forensic scientists could make some inferences, but the level of specificity was relatively low. This method did not provide individual identification or unique genetic information.
However, with advancements in DNA analysis and the development of DNA profiling techniques, such as polymerase chain reaction (PCR) and short tandem repeat (STR) analysis, forensic scientists gained a more powerful tool for linking biological samples to specific individuals. DNA profiling surpassed blood typing as the gold standard for forensic identification in the 1990s and has since revolutionized the field of forensic science, enabling more accurate and precise identification of individuals from biological samples such as blood, saliva, hair, and other tissues.