someone referred this forensic "exchange" (but couldn't remember the name) in the last couple of days........it is certainly important to the discussion at hand......
II. The exchange principle
Another important concept is that of the “Exchange Principle”. This principle was first articulated by theFrench scientist Edmond Locard and is often called the “Locard Exchange Principle”. Locard believed that when a criminal came into contact with another person or place, small items such as hairs or fibers would beleft by one person and perhaps picked up by the other. The "Locard Exchange Principle" can be stated as"When any two objects come into contact there is always a transfer from one object to the other." To quote Locard: “Wherever he steps, whatever he touches, whatever he leaves, even unconsciously, will serve as asilent witness against him. Not only his fingerprints or his footprints, but his hair, the fibers from his clothes,the glass he breaks, the tool mark he leaves, the paint he scratches, the blood or semen he deposits or collects. All of these and more, bear mute witness against him. This is evidence that does not forget. It is not confusedby the excitement of the moment. It is not absent because human witnesses are. It is factual evidence. Physical evidence cannot be wrong, it cannot perjure itself, it cannot be wholly absent. Only its interpretation can err.Only human failure to find it, study and understand it, can diminish its value." Professor Edmond Locard(1877-1966).
http://faculty.uml.edu/Nelson_Eby/89.215/Assignments/Introduction.pdf
Secondly, tissue under a nail of a stripper, lapdancer, escort, surely doesn't equate to rape.