Why have animal welfare groups criticized the use of mice in medical research?

Animal welfare groups have criticized the use of mice in medical research primarily due to ethical concerns regarding the treatment of sentient beings that are capable of experiencing pain and distress. Because mice cannot consent to participate in experiments, critics argue that it is morally problematic to subject them to procedures that may cause suffering or death for the sake of human benefit.12

A significant point of contention is the regulatory framework in the United States. While the Animal Welfare Act (AWA) establishes standards for the housing and handling of many research animals, it explicitly excludes mice bred for research purposes from its protections. Although these animals are covered under other policies—such as the Public Health Service Policy on Humane Care and Use of Laboratory Animals—critics often argue that existing regulations are insufficient to prevent abuse.32

Consequently, many welfare organizations advocate for the "three Rs" principle—replacement, reduction, and refinement—or call for a complete end to animal testing, emphasizing that alternative methods like cell cultures and computer modeling should be prioritized.24