Abstract
Summary One of the problems in dealing with the hormone effects on the breast is that we have a number of specialists who talk about observations in their own field, but who also tend to extrapolate into other fields. I refer particularly to interpretations by clinicians, biochemists, pathologists and epidemiologists. The difficulty for those who talk about aspects that are not their field of specialisation is that they may lead to distortions. I am a histopathologist, and my daily activity is to judge tissue based on microscopic morphology which is a true record and not a distortion. The remarks that I shall make are based on morphological studies in breast tissue, to emphasise some points of relevance to the general topic that we are addressing today.