We deal with this issue with the school, and, at least in Missouri, it falls under the general federal disability statutes. Basically you have to fall under the definition of "disability" to be able to force us to allow you to bring a companion animal. It's not enough that a doctor says that it would help them cope with the stresses of school. There has to be an actual diagnosis of a physical or mental disability that significantly impairs a life function, and a determination that the companion animal addresses that disability in some way.