The main arguments about animal research are:

A. Supporters of the use of animals in experiments, such as the British Royal Society, argue that virtually every medical achievement in the 20th century relied on the use of animals in some way.
B. The Institute for Laboratory Animal Research of the United States National Academy of Sciences has argued that animal research cannot be replaced by even sophisticated computer models, which are unable to deal with the extremely complex interactions between molecules, cells, tissues, organs, organisms and the environment.
C. Animal rights organizations—such as People for the Ethical Treatment of Animals (PETA) and British Union for the Abolition of Vivisection (BUAV, now Cruelty Free International) —question the need for and legitimacy of animal testing, arguing that it is cruel and poorly regulated, that medical progress is actually held back by misleading animal models that cannot reliably predict effects in humans, that some of the tests are outdated, that the costs outweigh the benefits, or that animals have the intrinsic right not to be used or harmed in experimentation.
D. Many people worldwide support the use of animals in biomedical research, but the animals must be treated humanely under the close monitoring of governments.