The ethics of animal research and testing: A US perspective

•The burgeoning field of adjunct and complementary methods to animal research and testing, including computer simulations and micro-physiological systems, has given rise to a debate about the ethics of animal research and testing.•Some argue the animal research and testing is an outdated science, whereas others contend regulated animal research and testing is the best available science.•A historical overview of the evolution of US federal regulations and ethical principles guiding animal research and testing over the past century can help shed light on this debate.