The debate over animal use in biomedical research has evolved dramatically over 150 years, from complete permissiveness to the current 3Rs framework, with ongoing tension between welfare and medical necessity.
The ongoing animal research debate involves genuine uncertainty about both animal welfare and the indispensability of animal models. Animal research has contributed to important medical advances — but the high failure rate of animal models in predicting human outcomes raises questions about whether the welfare cost is justified by the scientific return. The development of organoids, organ-on-a-chip systems, and in silico models is advancing rapidly. The welfare case is not for immediate abolition but for dramatically increased investment in replacement methods and more rigorous application of the 3Rs to every animal research protocol.