Intelligent design begins with observations about the types of information produced by intelligent agents. Design theorists argue that intelligent design constitutes a valid scientific research program aimed at understanding the effects of intelligence in the natural world (http://www.theism.net/article/16).
Most definitions of modern science describe a methodology of finding testable explanations of the universe. I often hear evolution is a theory not a fact. A scientific theory explains the facts and is verifiable or demonstrable. Evolution is one of the most validated theories around. I propose intelligent design is not science. It is not verifiable and its challenges to evolution.
To allow intelligent design into science you would need to change the definition of science and drop the testable requirements. I propose it should not be taught as legitimate course