Dr. Young offers only opinions made to a “reasonable degree of medical certainty.” Although the courts in Missouri and elsewhere have never defined this term, Dr. Young is clear about this for himself. He is “reasonably medically certain” when he is certain of the truth of his opinion after a careful forensic and medical analysis. Although it is not possible for him to be “absolute” in his certainty (he is not God), Dr. Young believes what he offers as opinions are true. If the limitations of science do not allow him to offer an opinion with certainty, he does not offer it. He does not speculate.