Are They Miracles Or Natural Spontaneous Remissions?

With the soon-to-be Sainthood of Mother Teresa comes discussion of how someone is declared a Saint by the Catholic Church.  Traditionally, for an individual to be declared a Saint, two "certified" miracles must be credited to prayer directed to the prospective Saint.  Left out of the Church's declaration regarding these miracles is skeptical consideration of the natural and frequent phenomenon of spontaneous remission of medical problems, to include serious forms of cancer.