This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Sexual offences and infanticide, Subject name: Forensic Medicine
Evidence not used in rape is 
Select and explain. 
A. Semen in vagina, B. Semen on clothes, C. Presence of smegma bacilli in vagina, D. Presence of smegma under prepuce
D: Presence of smegma under prepuce
Answer: D: Presence of smegma under prepuce 
Explanation: In the uncircumcised penis the presence of smegma under the prepuce and on the corona glandis rules out complete penetration because smegma will be rubbed off during intercourse. Smegma usually requires 24 hours to redeposit. Presence of smegma indicates that no sexual intercourse with full penetration is taken place within 24 hours but absence of smegma will not indicate intercourse. Ref: FORENSIC MEDICINE AND TOXICOLOGY Dr PC IGNATIUS THIRD EDITION PAGE 305