Historically, biological and medical research has largely depended on rodents, which provide scientists with everything from cells and organs to behavioral data. It might mean that a number of researchers have published mouse studies in which their results reflect this male-induced stress effect — and they know nothing about it. People have not paid attention to this in the entire history of scientific research of animals, says Jeffrey Mogil, a pain researcher at McGill University and lead author of the study. I think that it may have confounded, to whatever degree, some very large subset of existing research. Moreover, the effect probably isnt limited to behavioral studies, because the organs and cells that are used in medical research, such as in cancer studies, often originate in rodents.