1. A diagnostic system for optically classifying cervical tissue into pathological classes, comprising: a source of optical radiation which induces at least one of a fluorescence and backscatter response in the cervical tissue, a detector which detects the response induced in the cervical tissue and produces a response signal, and a processor which compares the response signal with reference signals obtained from cervical tissue samples of known pathology by computing a distance between the response signal and the reference signals, wherein the reference signals are grouped into at least two pathological classes and the cervical tissue producing the response signal is assigned to the class which produces the smallest distance.